We give thanks to the financial support of the National Natural Science Foundation of China (11076109), the Hong Kong Scholars Program (XJ2014045, G-YZ67), the "1000 Talents Plan" of the Sichuan Province, the Talent Introduction Program of Sichuan University (YJ201410), and the Innovation and Creative Experiment Program of Sichuan University (20171060, 20170133).

1. Preparation of the Raw Materials
<ol>
	<li>Weigh all the required raw materials with an electronic scale by mass percentage (65% electrolytic Mn, 26% electrolytic Cu, 2% industrial pure Fe, 2% electrolytic Ni, 3% electrolytic Al, and 2% electrolytic Zn), as shown in Figure 1. 
	&#8203;NOTE: All these raw materials were commercially available.</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57180/57180fig1.jpg" /> 
Figure 1: Presentation of raw materials. The materials used include 65 wt% electrolytic Mn, 26 wt% electrolytic Cu, 2 wt% industrial pure Fe, 2 wt% electrolytic Ni, 2 wt% electrolytic Zn, and 3 wt% electrolytic Al. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/57180/57180fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
2. Melting and Casting Process
NOTE: The detailed steps of sand casting are shown in Figure 2.
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57180/57180fig2.jpg" /> 
Figure 2: Sand casting and molding steps. The main process includes pattern-making, mold-making, and a casting operation. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/57180/57180fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol>
	<li>To prepare patterns, make patterns according to the product drawing, and make sure that the size of the pattern is expanded to a certain extent to be liable for shrinkage and machining allowances. 
	NOTE: The pattern material used in this work is wood ( Figure 3) because a wood pattern is light, easy to work, and has a low cost and short production cycle.</li>
</ol>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57180/57180fig3.jpg" /> 
Figure 3: Patterns used in the casting mold. These wood patterns were used to obtain the shape of the castings. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/57180/57180fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>To prepare the molding sand, mix together the quartz sand with 4% - 8% sodium silicate. 
	NOTE: The sand diameter is about 0.4 mm and the particles are uniform.</li>
	<li>Complete the main molding process by hands.
	<ol>
		<li>First, put two patterns in the molding flask.</li>
		<li>Then, roll over the flask after ramming the molding sand around the patterns and withdraw the patterns from the sand.</li>
		<li>Finally, brush the surface of the sand mold with casting coating for improving the casting surface quality and reducing casting defects. 
		&#8203;NOTE: The molded sand mold is shown in Figure 4.</li>
		<li>To obtain a dry sand mold, put the mold in an oven at 180 &#176;C and bake it for more than 8 h before casting to enhance its strength and permeability, facilitate the melt filling, and ensure the quality of the casting products.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57180/57180fig4.jpg" /> 
Figure 4: The molded sand mold. It has two cavities and its surface has been covered with a coating. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/57180/57180fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
3. Induction of Melting
NOTE: Use a medium-frequency vacuum induction melting furnace.
<ol>
	<li>Open the furnace lid, put 20.8 kg of Mn, 8.32 kg of Cu, 0.64 kg of Ni, 0.64 kg of Fe, 0.64 kg of Zn, and 0.96 kg of Al materials in the crucible successively, and cover the materials with cryolite at last.</li>
	<li>Take out the casting mold from the oven and put it in the furnace; adjust its position for a successful pouring. Close the lid, vacuum the furnace, and then open the heat distribution system to start melting the alloy.</li>
	<li>When the metals start to melt, fill the furnace with argon to a 93-KPa negative pressure, to inhibit the splashing of the molten metal.</li>
	<li>After the alloy has melted, refine it for several minutes to reduce the harmful impurities and gas content. 
	NOTE: The melting procedure often includes smelting and refining.</li>
</ol>
4. Casting the Alloy
<ol>
	<li>Pour the molten metal smoothly into the casting mold after the refining process.</li>
	<li>After the molten metal is completely solidified, break the vacuum and take out the casting mold.</li>
	<li>Remove the castings from the casting mold when the temperature of the mold drops to a low level.</li>
</ol>
5. Pretreatment of the Castings
NOTE: The macrophotograph of the molded part is shown in Figure 5.
<ol>
	<li>Cut specimens from the casting by using a linear cutting machine. 
	&#8203;NOTE: The specimens for the X-ray diffractometer (XRD) measurements and the metallographic observation are in 10 x 10 x 1 mm3. The specimens for the dynamic thermomechanical analysis (DMA) possess a dimension of 0.8 x 10 x 35 mm3.</li>
</ol>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57180/57180fig5.jpg" /> 
Figure 5: The molded parts in the sand mold and the removed parts. Two castings were molded at one time. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/57180/57180fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
6. Heat Treatment
<ol>
	<li>Divide the polished specimens into seven groups and keep specimen #1 free of treatment, maintaining an as-cast state for comparison. Put the others in a box-type resistance oven for different heat treatments.</li>
	<li>Homogenize specimens #2 and #5 at 850 &#176;C for 24 h and, subsequently, quench them in cool water before aging them at 435 &#176;C, specimen #2 for 4 h and specimen #5 for 2 h.</li>
	<li>Solution-treat specimens #3 and #6 at 900 &#176;C for 1 h and, subsequently, quench them in cool water before aging them at 435 &#176;C, specimen #3 for 4 h and specimen #6 for 2 h.</li>
	<li>Age specimens #4 and #7 at 435 &#176;C for 4 h and 2 h, respectively.</li>
</ol>
7. Damping Capacity Test
<ol>
	<li>Use a Dynamic Mechanical Analysis (DMA) to measure the damping capacity of the specimens17. 
	NOTE: The test mode is strain sweep at room temperature.</li>
	<li>During the test, detect the phase angle &#948; between the stress and the strain (as shown in Figure 6).</li>
	<li>Characterize the damping capacity by Q-1, which can be determined by the following formula. 
	Q-1&#160;= Tan&#160;&#948;</li>
</ol>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/57180/57180fig6.jpg" /> 
Figure 6: The fixture construction and testing principle of the DMA. ( a) This panel shows the double cantilever fixture of the DMA. ( b) This panel shows the relationship of the applied sinusoidal stress to the strain and the resultant phase lag. The values of the lag between the stress and the strain, as well as the modulus, can be calculated by formulae. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/57180/57180fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
8. Sample Characterization
<ol>
	<li>Electrolytic polishing and metallographic observation
	<ol>
		<li>For a dendrite microstructure observation, etch all specimens for about 1 min in a mixed solution of perchloric acid and absolute alcohol at 1:27.</li>
		<li>Then, clean the specimens with acetone, dry the sample with a blower, and observe the dendritic structure with a metallographic microscope.</li>
	</ol>
	</li>
	<li>Phase structure characterization
	<ol>
		<li>Characterize the phase structure and the lattice parameters of the specimens by X-ray diffraction (XRD) with CuK&#945; radiation12,22. 
		NOTE: Use a scan speed at 2&#176;/min. Before the XRD measurement, prepare the specimens carefully by removing any surface stress.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Zener, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Elasticity and anelasticity of metals. , (1948).</li><li>Jensen, J. W., Walsh, D. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Manganese-Copper+damping+alloys.">Manganese-Copper damping alloys.</a> Bulletin 624. , (1965).</li><li>Wang, X. Y., Peng, W. Y., Zhang, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Martensitic+twins+and+antiferromagnetic+domains+in+gamma-MnFe(Cu)+alloy.">Martensitic twins and antiferromagnetic domains in gamma-MnFe(Cu) alloy.</a> Materials Science and Engineering A. 438, 194-197 (2006).</li><li>Wang, X. Y., Zhang, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+twin+boundaries+in+Mn-based+shape+memory+alloy:+a+HRTEM+study+and+the+strain+energy+driving+force.">Structure of twin boundaries in Mn-based shape memory alloy: a HRTEM study and the strain energy driving force.</a> Acta Materialia. 55 (15), 5169-5176 (2007).</li><li>Yin, F. X., Ohsawa, Y., Sato, A., Kawahara, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decomposition+behavior+of+the+gamma(Mn)+solid+solution+in+a+Mn-20Cu-8Ni-2Fe+(at%)+alloy+studied+by+a+magnetic+measurement.">Decomposition behavior of the gamma(Mn) solid solution in a Mn-20Cu-8Ni-2Fe (at%) alloy studied by a magnetic measurement.</a> Materials Transactions,JIM. 40 (5), 451-454 (1999).</li><li>Dean, R. S., Potter, E. V., Long, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+transitional+structures+in+Copper-Manganese+alloys.">Properties of transitional structures in Copper-Manganese alloys.</a> Metallurgical and Materials Transactions, ASM. 34, 465-500 (1945).</li><li>Yin, F. X., Ohsawa, Y., Sato, A., Kawahara, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+dependent+damping+behavior+in+a+Mn-18Cu-6Ni-2Fe+alloy+continuously+cooled+in+different+rates+from+the+solid+solution+temperature.">Temperature dependent damping behavior in a Mn-18Cu-6Ni-2Fe alloy continuously cooled in different rates from the solid solution temperature.</a> Scripta Materialia. 38 (9), 1314-1346 (1998).</li><li>Findik, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvements+in+spinodal+alloys+from+past+to+present.">Improvements in spinodal alloys from past to present.</a> Materials and Design. 42 (42), 131-146 (2012).</li><li>Yan, J. Z., Li, N., Fu, X., Zhang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+strengthening+effect+of+spinodal+decomposition+and+twinning+structure+in+MnCu-based+alloy.">The strengthening effect of spinodal decomposition and twinning structure in MnCu-based alloy.</a> Materials Science and Engineering A. 618, 205-209 (2014).</li><li>Soriano-Vargas, O., Avila-Davila, E. O., Lopez-Hirata, V. M., Cayetano-Castro, N., Gonzalez-Velazquez, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+spinodal+decomposition+on+the+mechanical+behavior+of+Fe-Cr+alloys.">Effect of spinodal decomposition on the mechanical behavior of Fe-Cr alloys.</a> Materials Science and Engineering A. 527 (12), 2910-2914 (2010).</li><li>Yin, F. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Damping+behavior+characterization+of+the+M2052+alloy+aimed+for+practical+application.">Damping behavior characterization of the M2052 alloy aimed for practical application.</a> Acta Metallurgica Sinica. 39 (11), 1139-1144 (2003).</li><li>Yin, F. X., Ohsawa, Y., Sato, A., Kohji, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decomposition+of+high+temperature+gamma(Mn)+phase+during+continuous+cooling+and+resultant+damping+behavior+in+Mn74.8Cu19.2Ni4.0Fe2.0+and+Mn72.4Cu20.0Ni5.6Fe2.0+alloys.">Decomposition of high temperature gamma(Mn) phase during continuous cooling and resultant damping behavior in Mn74.8Cu19.2Ni4.0Fe2.0 and Mn72.4Cu20.0Ni5.6Fe2.0 alloys.</a> Materials Transactions, JIM. 39 (8), 841-848 (1998).</li><li>Sakaguchi, T., Yin, F. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Holding+temperature+dependent+variation+of+damping+capacity+in+a+MnCuNiFe+damping+alloy.">Holding temperature dependent variation of damping capacity in a MnCuNiFe damping alloy.</a> Scripta Materialia. 54 (2), 241-246 (2006).</li><li>Tanji, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+damping+performance+of+M2052+alloy+at+cryogenic+temperatures.">Measurement of damping performance of M2052 alloy at cryogenic temperatures.</a> Journal of Alloys and Compounds. 355 (1-2), 207-210 (2003).</li><li>Yin, F. X., Iwasaki, S., Sakaguchi, T., Nagai, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Susceptibility+of+damping+behavior+to+the+solidification+condition+in+the+as-cast+M2052+high-damping+alloy.">Susceptibility of damping behavior to the solidification condition in the as-cast M2052 high-damping alloy.</a> Key Engineering Materials. 319, 67-72 (2006).</li><li>Yin, F. X., Ohsawa, Y., Sato, A., Kawahara, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+the+strain-amplitude+and+frequency+dependent+damping+capacity+in+the+M2052+alloy.">Characterization of the strain-amplitude and frequency dependent damping capacity in the M2052 alloy.</a> Materials Transactions, JIM. 42 (3), 385-388 (2001).</li><li>Zhong, Z. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mn+segregation+dependence+of+damping+capacity+of+as-cast+M2052+alloy.">Mn segregation dependence of damping capacity of as-cast M2052 alloy.</a> Materials Science and Engineering A. 660, 97-101 (2016).</li><li>Liu, W. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+cast-aged+MnCuNiFeZnAl+alloy+with+good+damping+capacity+and+high+service+temperature+toward+engineering+application.">Novel cast-aged MnCuNiFeZnAl alloy with good damping capacity and high service temperature toward engineering application.</a> Materials Design. 106, 45-50 (2016).</li><li>Cowlam, N., Shamah, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+diffraction+study+of+y-Mn-Cu+alloys.">A diffraction study of y-Mn-Cu alloys.</a> Journal of Physics F: Metal Physics. 11 (1), 27-43 (1981).</li><li>Yan, J. Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+pre-deformation+and+subsequent+aging+on+the+damping+capacity+of+Mn-20+at.%Cu-5+at.%Ni-2+at.%Fe+alloy.">Effect of pre-deformation and subsequent aging on the damping capacity of Mn-20 at.%Cu-5 at.%Ni-2 at.%Fe alloy.</a> Advanced Engineering Materials. 17 (9), 1332-1337 (2015).</li><li>Zhang, Y., Li, N., Yan, J. Z., Xie, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+the+precipitated+second+phase+during+aging+on+the+damping+capacity+degradation+behavior+of+M2052+alloy.">Effect of the precipitated second phase during aging on the damping capacity degradation behavior of M2052 alloy.</a> Advances in Materials Research. 873, 36-41 (2014).</li><li>Yin, F. X., Ohsawa, Y., Sato, A., Kawahara, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=X-ray+diffraction+characterization+of+the+decomposition+behavior+of+gamma(Mn)+phase+in+a+Mn-30+at.%+Cu+alloy.">X-ray diffraction characterization of the decomposition behavior of gamma(Mn) phase in a Mn-30 at.% Cu alloy.</a> Scripta Materialia. 40 (9), 993-998 (1999).</li><li>Yin, F. X., Ohsawa, Y., Sato, A., Kawahara, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+decomposition+of+the+gamma+phase+in+a+Mn-30+at.%+Cu+alloy+during+aging.">Phase decomposition of the gamma phase in a Mn-30 at.% Cu alloy during aging.</a> Acta Materialia. 48 (6), 1273-1282 (2000).</li><li>Ritchie, I. G., Sprungmann, K. W., Sahoo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Internal-friction+in+Sonoston+-+a+high+damping+Mn/Cu-based+alloy+for+marine+propeller+applications.">Internal-friction in Sonoston - a high damping Mn/Cu-based alloy for marine propeller applications.</a> Journal De Physique. 46 (C-10), 409-412 (1985).</li><li>Kawahara, K., Sakuma, N., Nishizaki, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Fourth+Elements+on+Damping+Capacity+of+Mn-20Cu-5Ni+Alloy.">Effect of Fourth Elements on Damping Capacity of Mn-20Cu-5Ni Alloy.</a> Journal of the Japan Institute of Metals. 57 (9), 1097-1100 (1993).</li></ol>

The authors have nothing to disclose.

To ensure that this kind of as-cast Mn-Cu-based alloy possesses both&#160;superior damping capacity and excellent mechanical properties, it is necessary to ensure that the castings have a stable chemical composition, a high purity, and an excellent crystal structure. Therefore, strict quality control is necessary for the smelting, pouring, and heat treatment processes.
Firstly, it is necessary to choose the proper ingredients for the alloy. It should be considered that the added alloy elements...

Since the Mn-Cu alloys were found by Zener to have&#160;damping capacity1, they have received widespread attention and research2. The advantages of Mn-Cu alloy are that it has&#160;high damping capacity, especially at low strain amplitudes, and its damping capacity cannot be disturbed by a magnetic field, which is quite different from ferromagnetic damping alloys. The high damping capacity of Mn-Cu-based alloys can be mainly attributed to the movability of the internal boundaries, mainly including twin boundaries and phase boundaries, which are generated in the face-centered-cubic-to-face-centered-tetragonal (f.c.c.-f.c.t.) phase transition under the martensite transformation temperature (Tt)3. It has been found that Tt depends directly on the Mn content in the Mn-Cu-based alloy4,5; that is, the higher the Mn content, the higher the Tt and the better the damping capacity of the material. The alloy, which contains more than 80 at% manganese, was found to have&#160;high damping capacity and optimum strength when quenched from the solid-solution temperature6. However, the higher Mn concentration in the alloy would directly cause the alloy to be more brittle and have a lower elongation, impact toughness, and a worse corrosion resistance, which means the alloy will not meet the engineering requirements. Previous research findings revealed that an aging treatment under suitable conditions is an effective way to reconcile this problem; for instance, Mn-Cu-based damping alloys containing 50 - 80 at% Mn can also obtain a high Tt and&#160;favorable damping capacity by an aging treatment in the appropriate temperature range7. This is due to the decomposition of the &#947;-parent phase into nanoscale Mn-rich regions and nanoscale Cu-rich regions while aging in the temperature range of the miscibility gap8,9,10, which is considered to improve Tt of this alloy along with its damping capacity. Clearly, it is an effectual method which can combine&#160;high damping capacity with excellent workability.
M2052 alloy used for forging forming, a representative Mn-Cu-based high-damping alloy with medium Mn content developed by Kawahara et al.11, has been extensively studied in the last few decades. Researchers found that M2052 alloy has a good sweet spot between damping capacity, yield strength, and workability. Compared with the forging technique, casting has been widely used so far due to the simple molding process, low production costs, and high productivity, etc. The influential factors (e.g., oscillation frequency, strain amplitude, cooling velocity, heat treatment temperature/time, etc.) on the damping capacity, microstructure, and damping mechanism of M2052 alloy have been studied by some researchers12,13,14,15,16,17,18. Nevertheless, the casting performance of M2052 alloy is inferior, for instance, a wide range of crystallization temperature, the occurrence of casting porosity, and concentrated shrinkage, eventually resulting in the unsatisfactory mechanical properties of the castings.
The purpose of this paper is to provide the industrial field with a feasible method of obtaining a cast Mn-Cu based alloy with excellent properties which can be used in machinery and in the precision instruments industry to reduce vibration and ensure the product quality. According to the effect of alloying elements on the phase transformation and the casting performance, Al element is considered to reduce the &#947;-phase region and the stability of the &#947; phase, which can make the &#947; phase more easily transform into a &#947;&#39; phase with micro-twins. Moreover, the solution of Al atoms in the &#947; phase will increase the strength of the alloy, which can improve the mechanical properties. Also, Al element is one of the important elements which can improve the casting properties of Mn-Cu alloy. Zn element is beneficial to improving the casting and damping properties of the alloy. Finally, 2 wt% Zn and 3 wt% Al were added to the MnCuNiFe quaternary alloy in this work and a new cast Mn-26Cu-12Ni-2Fe-2Zn-3Al (wt%) alloy was developed. Furthermore, several different heat treatment methods are used in this work and their distinct effects are discussed as follows. The homogenization treatment was used to reduce dendrite segregation. The solution treatment was used for impurities immobilization. The aging treatment is used for triggering spinodal decomposition; meanwhile, the various aging times are used for seeking out the optimizing parameters for both excellent damping capacity and a high service temperature. Ultimately, a preferable heat treatment method was screened for superior damping capacity, as well as a high service temperature.
It turns out that the maximum internal friction (Q-1) and the highest service temperature can be achieved concurrently by aging the alloy at 435 &#176;C for 2 h. Because of the simplicity and efficiency of this preparation method, a novel as-cast Mn-Cu-based damping alloy with excellent performance can be produced, which is of important practical significance for its engineering application. This method is particularly suitable for the preparation of casting Mn-Cu-based high damping alloy which can be used for vibration reduction.

<table><tbody><tr><td>manganese</td><td>Daye Nonferrous Metals Group Holdings Co., Ltd.</td><td>DJMnB</td><td>produced by electrolysis</td></tr><tr><td>copper</td><td>Daye Nonferrous Metals Group Holdings Co., Ltd.</td><td>Cu-CATH-2</td><td>produced by electrolysis</td></tr><tr><td>Nickel</td><td>Daye Nonferrous Metals Group Holdings Co., Ltd.</td><td>Ni99.99</td><td>produced by electrolysis</td></tr><tr><td>Iron</td><td>Ningbo Jiasheng Metal Materials Co., Ltd.</td><td>YT01</td><td>industrial pure Fe</td></tr><tr><td>Zinc</td><td>Daye Nonferrous Metals Group Holdings Co., Ltd.</td><td>0#</td><td>produced by electrolysis</td></tr><tr><td>Aluminum</td><td>Daye Nonferrous Metals Group Holdings Co., Ltd.</td><td>Al99.90</td><td>produced by electrolysis</td></tr></tbody></table>

an available technique for preparation of new cast mncunifeznal alloy with superior damping capacity and high service temperature

Manganese (Mn)-copper (Cu)-based alloys have been found to have&#160;damping capacity and can be used to reduce harmful vibrations and noise effectively. M2052 (Mn-20Cu-5Ni-2Fe, at%) is an important branch of Mn-Cu-based alloys, which possesses both excellent damping capacity and processability. In recent decades, lots of studies have been carried out on the performance optimization of M2052, improving the damping capacity, mechanical properties, corrosion resistance, and service temperature, etc. The major methods of performance optimization are alloying, heat treatment, pretreatment, and different ways of molding etc., among which alloying, as well as adopting a reasonable heat treatment, is the simplest and most effective method to obtain perfect and comprehensive performance. To obtain the M2052 alloy with excellent performance for casting molding, we propose to add Zn and Al to the MnCuNiFe alloy matrix and use a variety of heat treatment methods for a comparison in the microstructure, damping capacity, and service temperature. Thus, a new type of cast-aged Mn-22.68Cu-1.89Ni-1.99Fe-1.70Zn-6.16Al (at.%) alloy with&#160;superior damping capacity and high service temperature is obtained by an optimized heat treatment method. Compared with the forging technique, cast molding is simpler and more efficient, and the damping capacity of this as-cast alloy is excellent. Therefore, there is a suitable reason to think that it is a good choice for engineering applications.

Figure 7&#160;shows the dependency of the damping capacity on the strain amplitude for the as-cast MnCuNiFeZnAl alloy specimens #1 - #7 and as-cast M2052. The results show that the damping capacity of specimen #1 is higher than that of cast M2052 alloy (as shown in Figure 7a) and the traditional forged M2052 high-damping alloy mentioned in previous articles20,21. Moreover...

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An Available Technique for Preparation of New Cast MnCuNiFeZnAl Alloy with Superior Damping Capacity and High Service Temperature

Here we present a protocol to obtain a novel Mn-Cu-based alloy with excellent comprehensive performances by a high-quality smelting technology and reasonable heat treatment methods.

Manganese (Mn)-copper (Cu)-based alloys have been found to have&#160;damping capacity and can be used to reduce harmful vibrations and noise effectively. ...

an-available-technique-for-preparation-new-cast-mncunifeznal-alloy

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

6.8K Views.  Sichuan University. Here we present a protocol to obtain a novel Mn-Cu-based alloy with excellent comprehensive performances by a high-quality smelting technology and reasonable heat treatment methods. 

Video: An Available Technique for Preparation of New Cast MnCuNiFeZnAl Alloy with Superior Damping Capacity and High Service Temperature

Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions

Estimates of the primitive upper mantle (PUM) composition reveal a depletion in many of the siderophile (iron-loving) elements, thought to result from their extraction to the core during terrestrial accretion. Experiments to investigate the partitioning of these elements between metal and silicate melts suggest that the PUM composition is best matched if metal-silicate equilibrium occurred at high pressures and temperatures, in a deep magma ocean environment. The behavior of the most highly siderophile elements (HSEs) during this process however, has remained enigmatic. Silicate run-products from HSE solubility experiments are commonly contaminated by dispersed metal inclusions that hinder the measurement of element concentrations in the melt. The resulting uncertainty over the true solubility and metal-silicate partitioning of these elements has made it difficult to predict their expected depletion in PUM. Recently, several studies have employed changes to the experimental design used for high pressure and temperature solubility experiments in order to suppress the formation of metal inclusions. The addition of Au (Re, Os, Ir, Ru experiments) or elemental Si (Pt experiments) to the sample acts to alter either the geometry or rate of sample reduction respectively, in order to avoid transient metal oversaturation of the silicate melt. This contribution outlines procedures for using the piston-cylinder and multi-anvil apparatus to conduct solubility and metal-silicate partitioning experiments respectively. A protocol is also described for the synthesis of uncontaminated run-products from HSE solubility experiments in which the oxygen fugacity is similar to that during terrestrial core-formation. Time-resolved LA-ICP-MS spectra are presented as evidence for the absence of metal-inclusions in run-products from earlier studies, and also confirm that the technique may be extended to investigate Ru. Examples are also given of how these data may be applied.

We present a procedure to determine the metal-silicate partitioning of siderophile elements, emphasizing techniques that suppress the formation of metal inclusions in experiments for the noble metals. The results of these experiments are used to demonstrate the effect of core-formation on the highly siderophile element composition of the mantle.

Estimates of the primitive upper mantle (PUM) composition reveal a depletion in many of the siderophile (iron-loving) elements, thought to result from ...

Chemistry

High-Sensitivity Nuclear Magnetic Resonance at Giga-Pascal Pressures: A New Tool for Probing Electronic and Chemical Properties of Condensed Matter under Extreme Conditions

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their electronic properties. The application of high pressure enables one to synthesize new materials, but the response of known materials to high pressure is a very useful tool for studying their electronic structure and developing theories. For example, high-pressure synthesis might be at the origin of life; and understanding the behavior of small molecules under extreme pressure will tell us more about fundamental processes in our universe. It is no wonder that there has always been great interest in having NMR available at high pressures. Unfortunately, the desired pressures are often well into the Giga-Pascal (GPa) range and require special anvil cell devices where only very small, secluded volumes are available. This has restricted the use of NMR almost entirely in the past, and only recently, a new approach to high-sensitivity GPa NMR, which has a resonating micro-coil inside the sample chamber, was put forward. This approach enables us to achieve high sensitivity with experiments that bring the power of NMR to Giga-Pascal pressure condensed matter research. First applications, the detection of a topological electronic transition in ordinary aluminum metal and the closing of the pseudo-gap in high-temperature superconductivity, show the power of such an approach. Meanwhile, the range of achievable pressures was increased tremendously with a new generation of anvil cells (up to 10.1 GPa), that fit standard-bore NMR magnets. This approach might become a new, important tool for the investigation of many condensed matter systems, in chemistry, geochemistry, and in physics, since we can now watch structural changes with the eyes of a very versatile probe.

Nuclear magnetic resonance is one of the most important spectroscopic tools. Here, the development of a new approach under high pressure, currently up to 10.1 GPa, is presented. This opens a new window into condensed matter physics and chemistry, where high-pressure research is of great importance.

Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their ...

Casting Protocols for the Production of Open Cell Aluminum Foams by the Replication Technique and the Effect on Porosity

Metal foams are interesting materials from both a fundamental understanding and practical applications point of view. Uses have been proposed, and in many cases validated experimentally, for light weight or impact energy absorbing structures, as high surface area heat exchangers or electrodes, as implants to the body, and many more. Although great progress has been made in understanding their structure-properties relationships, the large number of different processing techniques, each producing material with different characteristics and structure, means that understanding of the individual effects of all aspects of structure is not complete. The replication process, where molten metal is infiltrated between grains of a removable preform material, allows a markedly high degree of control and has been used to good effect to elucidate some of these relationships. Nevertheless, the process has many steps that are dependent on individual &#8220;know-how&#8221;, and this paper aims to provide a detailed description of all stages of one embodiment of this processing method, using materials and equipment that would be relatively easy to set up in a research environment. The goal of this protocol and its variants is to produce metal foams in an effective and simple way, giving the possibility to tailor the outcome of the samples by modifying certain steps within the process. By following this, open cell aluminum foams with pore sizes of 1&#8211;2.36 mm diameter and 61% to 77% porosity can be obtained.

Replication is one of the processing techniques used for the production of porous metal sponges. In this paper one implementation of the method for the production of open celled porous aluminum is shown in detail.

Metal foams are interesting materials from both a fundamental understanding and practical applications point of view. Uses have been proposed, and in many ...

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) and Electron Beam Melting (EBM). In spite of its potential processing capability, the direct AM method has several disadvantages such as high cost, poor surface finish of final products, limitation in material selection, high thermal stress, and anisotropic properties of parts. We propose a cost-effective method to manufacture 3D lattice metals. The objective of this study is to provide a detailed protocol on fabrication of 3D lattice metals having a complex shape and a thin wall thickness; e.g., octet truss made of Al and Cu alloys having a unit cell length of 5 mm and a cell wall thickness of 0.5 mm. An overall experimental procedure is divided into eight sections: (a) 3D printing of sacrificial patterns (b) melt-out of support materials (c) removal of residue of support materials (d) pattern assembly (e) investment (f) burn-out of sacrificial patterns (g) centrifugal casting (h) post-processing for final products. The suggested indirect AM technique provides the potential to manufacture ultra-lightweight lattice metals; e.g., lattice structures with Al alloys. It appears that the process parameters should be properly controlled depending on materials and lattice geometry, observing the final products of octet truss metals by the indirect AM technique.

An indirect additive manufacturing method combining a 3D printing of polymers with a centrifugal casting is outlined for manufacturing 3D octet truss metals (Al and Cu alloys) having a unit cell length of 5 mm with a wall thickness of 0.5 mm.

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) ...

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Nickel-Titanium (Ni-Ti) based alloy systems, especially, show large elastocaloric effects. Furthermore, exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. A scientific test rig has been designed to investigate these processes and the elastocaloric effects in SMAs. The realized test rig enables independent control of an SMA&#39;s mechanical loading and unloading cycles, as well as conductive heat transfer between SMA cooling elements and a heat source/sink. The test rig is equipped with a comprehensive monitoring system capable of synchronized measurements of mechanical and thermal parameters. In addition to determining the process-dependent mechanical work, the system also enables measurement of thermal caloric aspects of the elastocaloric cooling effect through use of a high-performance infrared camera. This combination is of particular interest, because it allows illustrations of localization and rate effects &#8212; both important for efficient heat transfer from the medium to be cooled.
The work presented describes an experimental method to identify elastocaloric material properties in different materials and sample geometries. Furthermore, the test rig is used to investigate different cooling process variations. The introduced analysis methods enable a differentiated consideration of material, process and related boundary condition influences on the process efficiency. The comparison of the experimental data with the simulation results (of a thermomechanically coupled finite element model) allows for better understanding of the underlying physics of the elastocaloric effect. In addition, the experimental results, as well as the findings based on the simulation results, are used to improve the material properties.

Experimental methods for investigation of solid state cooling processes and characterization of elastocaloric material properties of Shape Memory Alloys (SMA) are presented. A custom-built test rig has been designed for controlling and comprehensive monitoring of elastocaloric cooling processes. Furthermore, it provides a validation platform for thermomechanically coupled modeling approaches.

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor ...

Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the efficiency and lowering the development time of such processes, whilst reducing costs involved in trial-and-error prototyping. Recent focus on the substitution of steel components with aluminum alloy alternatives in the automotive and aerospace sectors has increased the need to simulate the forming behavior of such alloys for ever more complex component geometries. However these alloys, and in particular their high strength variants, exhibit limited formability at room temperature, and high temperature manufacturing technologies have been developed to form them. Consequently, advanced constitutive models are required to reflect the associated temperature and strain rate effects. Simulating such behavior is computationally very expensive using conventional FE simulation techniques.
This paper presents a novel Knowledge Based Cloud FE (KBC-FE) simulation technique that combines advanced material and friction models with conventional FE simulations in an efficient manner thus enhancing the capability of commercial simulation software packages. The application of these methods is demonstrated through two example case studies, namely: the prediction of a material's forming limit under hot stamping conditions, and the tool life prediction under multi-cycle loading conditions.

The following paper presents a novel FE simulation technique (KBC-FE), which reduces computational cost by performing simulations on a cloud computing environment, through the application of individual modules. Moreover, it establishes a seamless collaborative network between world leading scientists, enabling the integration of cutting edge knowledge modules into FE simulations.

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the ...

Experimental Procedure for Warm Spinning of Cast Aluminum Components

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to improve material properties. With a wide array of processing parameters which can affect both the shape attained and resulting material properties, this type of processing is notoriously difficult to commission. A simplified, light-duty version of the process has been designed and implemented for full-size automotive wheels. The apparatus is intended to assist in understanding the deformation mechanisms and the material response to this type of processing. An experimental protocol has been developed to prepare for, and subsequently perform forming trials and is described for as-cast A356 wheel blanks. The thermal profile attained, along with instrumentation details are provided. Similitude with full-scale forming operations which impart significantly more deformation at faster rates is discussed.

An experimental protocol for instrumented warm rotary forming of cast aluminum alloys employing a bespoke industrially scaled apparatus is presented. Experimental considerations including thermal and mechanical effects are discussed, as well as similitude with full-scale processing of automotive wheels.

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to ...

Fused Filament Fabrication (FFF) of Metal-Ceramic Components

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with diverse customization options and favorable production methods is increasing continuously. With fused filament fabrication (FFF), it is possible to produce large and complex components quickly with high material efficiency. In FFF, a continuous thermoplastic filament is melted in a heated nozzle and deposited below. The computer-controlled print head is moved in order to build up the desired shape layer by layer. Investigations regarding printing of metals or ceramics are increasing more and more in research and industry. This study focuses on additive manufacturing (AM) with a multi-material approach to combine a metal (stainless steel) with a technical ceramic (zirconia: ZrO2). Combining these materials offers a broad variety of applications due to their different electrical and mechanical properties. The paper shows the main issues in preparation of the material and feedstock, device development, and printing of these composites.

Fused Filament Fabrication FFF of Metal-Ceramic Components

This study shows multi-material additive manufacturing (AM) using fused filament fabrication (FFF) of stainless steel and zirconia.

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with ...

Negative Additive Manufacturing of Complex Shaped Boron Carbides

Boron carbide (B4C) is one of the hardest materials in existence. However, this attractive property also limits its machineability into complex shapes for high wear, high hardness, and lightweight material applications such as armors. To overcome this challenge, negative additive manufacturing (AM) is employed to produce complex geometries of boron carbides at various length scales. Negative AM first involves gelcasting a suspension into a 3D-printed plastic mold. The mold is then dissolved away, leaving behind a green body as a negative copy. Resorcinol-formaldehyde (RF) is used as a novel gelling agent because unlike traditional hydrogels, there is little to no shrinkage, which allows for extremely complex molds to be used. Furthermore, this gelling agent can be pyrolyzed to leave behind ~50 wt% carbon, which is a highly effective sintering aid for B4C. Due to this highly homogenous distribution of in situ carbon within the B4C matrix, less than 2% porosity can be achieved after sintering. This protocol highlights in detail the methodology for creating near fully dense boron carbide parts with highly complex geometries.

A method called negative additive manufacturing is used to produce near fully dense complex shaped boron carbide parts of various length scales. This technique is possible via the formulation of a novel suspension involving resorcinol-formaldehyde as a unique gelling agent that leaves behind a homogenous carbon sintering aid after pyrolysis.

Boron carbide (B4C) is one of the hardest materials in existence. However, this attractive property also limits its machineability into complex shapes for ...

Fabrication of Mechanically Tunable and Bioactive Metal Scaffolds for Biomedical Applications

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness and low bioactivity of metals. In this study, we have developed a new method towards fabricating a new type of bioactive and mechanically reliable porous metal scaffolds-densified porous Ti scaffolds. The method consists of two fabrication processes, 1) the fabrication of porous Ti scaffolds by dynamic freeze casting, and 2) coating and densification of the porous scaffolds. The dynamic freeze casting method to fabricate porous Ti scaffolds allowed the densification of porous scaffolds by minimizing the chemical contamination and structural defects. The densification process is distinctive for three reasons. First, the densification process is simple, because it requires a control of only one parameter (degree of densification). Second, it is effective, as it achieves mechanical enhancement and sustainable release of biomolecules from porous scaffolds. Third, it has broad applications, as it is also applicable to the fabrication of functionally graded porous scaffolds by spatially varied strain during densification.

Bioactive and mechanically reliable metal scaffolds have been fabricated through a method which consists of two processes, dynamic freeze casting for the fabrication of porous Ti, and coating and densification of the Ti scaffolds. The densification process is simple, effective and applicable to the fabrication of functionally graded scaffolds.

Biometal systems have been widely used for biomedical applications, in particular, as load-bearing materials. However, major challenges are high stiffness ...