热处理对选区激光熔化成形M2052合金组织性能的影响
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摘要
目的综合提升选区激光熔化(Selective Laser Melting,SLM)成形M2052锰铜合金的力学性能。方法利用SLM技术成形M2052锰铜合金,并通过固溶、时效及固溶+时效等热处理方法对其成形态组织进行调控。通过扫描电子显微镜和X射线衍射仪,对合金的显微组织、晶粒形貌、拉伸断口形貌及物相组成进行分析,并通过拉伸性能、冲击性能测试,分别评价SLM成形及热处理后的屈服强度、抗拉强度、延伸率和冲击韧性。结果 SLM成形的M2052合金经过固溶处理后,形成了典型的类孪晶结构;时效处理后的组织和SLM成形态类似,形成了细微的亚孪晶组织;固溶+时效处理后,类孪晶组织粗大。四种状态的显微组织均由单相γ固溶体组成,时效态和固溶+时效态析出了α-Mn相,但时效态析出含量较多。SLM成形态具有较高的抗拉强度σb和屈服强度σp0.2(636 MPa和548 MPa),时效处理能提高合金的σb和σp0.2(707MPa和570MPa),但是冲击韧性和延伸率(5.5J和8.5%)较差;而固溶处理能显著提高合金的冲击韧性和延伸率(23.5 J和22.25%)。综合比较,固溶+时效态试样具有最好的力学性能(冲击韧性为17 J,延伸率为10.8%,σb为503 MPa和σp0.2为322.5 MPa)。断口分析表明,四种状态下均为韧性断裂。结论固溶+时效热处理可以在存在单相γ固溶体条件下析出少量的α-Mn相,综合提升锰铜合金的力学性能。
The work aims to improve the mechanical properties of M2052 MnCu alloy formed by selective laser melting(SLM). M2052 MnCu alloy was formed by SLM and the microstructure was controlled by heat treatment methods such as solution, aging, solution+aging, etc. The microstructure, grain morphology, tensile fracture morphology and phase composition of the alloy were analyzed by scanning electron microscopy and X-ray diffractometry. The yield strength, tensile strength, elongation and impact toughness after SLM forming and heat treatment were evaluated by tensile and impact property tests. The SLM-formed M2052 alloy presented a typical eutectic structure after solution treatment; the structure after aging treatment was similar to the morphology formed by SLM, showing a fine sub-twisted structure; and the eutectic structure after solution+aging treatment was coarse. The microstructures of the four states were composed of single-phase γ solid solution. The α-Mn phase precipitated in the aging state and the solution+aging state, but the precipitated content was more. The SLM formed morphology had a high tensile strength σb and a yield strength σp0.2(636 MPa and 548 MPa). The aging treatment could improve the σb andσp0.2(707 MPa and 570 MPa) of the alloy, but the impact toughness and elongation(5.5 J and 8.5%) was poor; and solution treatment could significantly improve the impact toughness and elongation of the alloy(23.5 J and 22.25%). Through comprehensive comparison, solution+aging samples had the best mechanical properties(the impact toughness of 17 J, the elongation of10.8%, σb of 503 MPa, and σp0.2 of 322.5 MPa). Fracture analysis showed that the four states had ductile fractures. Solution+aging heat treatment can precipitate a small amount of α-Mn phase in the presence of single-phase γ solid solution, thus comprehensively improving the mechanical properties of manganese-copper alloy.
The work aims to improve the mechanical properties of M2052 MnCu alloy formed by selective laser melting(SLM). M2052 MnCu alloy was formed by SLM and the microstructure was controlled by heat treatment methods such as solution, aging, solution+aging, etc. The microstructure, grain morphology, tensile fracture morphology and phase composition of the alloy were analyzed by scanning electron microscopy and X-ray diffractometry. The yield strength, tensile strength, elongation and impact toughness after SLM forming and heat treatment were evaluated by tensile and impact property tests. The SLM-formed M2052 alloy presented a typical eutectic structure after solution treatment; the structure after aging treatment was similar to the morphology formed by SLM, showing a fine sub-twisted structure; and the eutectic structure after solution+aging treatment was coarse. The microstructures of the four states were composed of single-phase γ solid solution. The α-Mn phase precipitated in the aging state and the solution+aging state, but the precipitated content was more. The SLM formed morphology had a high tensile strength σb and a yield strength σp0.2(636 MPa and 548 MPa). The aging treatment could improve the σb andσp0.2(707 MPa and 570 MPa) of the alloy, but the impact toughness and elongation(5.5 J and 8.5%) was poor; and solution treatment could significantly improve the impact toughness and elongation of the alloy(23.5 J and 22.25%). Through comprehensive comparison, solution+aging samples had the best mechanical properties(the impact toughness of 17 J, the elongation of10.8%, σb of 503 MPa, and σp0.2 of 322.5 MPa). Fracture analysis showed that the four states had ductile fractures. Solution+aging heat treatment can precipitate a small amount of α-Mn phase in the presence of single-phase γ solid solution, thus comprehensively improving the mechanical properties of manganese-copper alloy.
引文
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[2]BAIK S H.High damping Fe-Mn martensitic alloys for engineering applications[J].Nuclear engineering&design,2000,198(3):241-252.
[3]YU Xue-yong,GAO Guo-lin,YUAN Li.Research development of Fe-Mn based high damping alloys[J].Foundry technology,2012,33(7):774-776.
[4]陈一胜,刘萍,闫丰.铜阻尼合金的研究和发展现状[J].上海金属,2007,29(3):54-58.CHEN Yi-sheng,LIU Ping,YAN Feng.Research and development of copper damping alloys[J].Shanghai metal,2007,29(3):54-58.
[5]施瑞鹤,华瑞起,盛宗毅.锰铜高阻尼合金的熔炼[J].热加工工艺,1987(5):46-49.SHI Rui-he,HUA Rui-qi,SHENG Zong-yi.Melting of manganese-copper high damping alloy[J].Hot processing technology,1987(5):46-49.
[6]LIU K F,WANG T,HE Q.Development of high damping Mn-Cu alloy TIG welding wire MC7301 patent[J].Ship science and technology,1993(5):42-48.
[7]LU L,FUH J Y H,CHEN Z D.In-situ formation of TiCcomposite using selective laser melting[J].Materials research bulletin,2000,35:1555-1561.
[8]YIN F X,SATOSHI I,TAKUYA S,et al.The improved damping behavior of Mn-Cu high damping alloy obtained by solidification process control[J].Progress in physics,2006,26:323-331.
[9]WU Y Q,YIN F X,HONO K.The decomposedγ-phase microstructure in a Mn-Cu-Ni-Fe alloy studied by HRTEM and 3D atom probe[J].Scripta materialia,2002,46(10):717-722.
[10]ZHONG Y,SAKAGUCHI T,YIN F.Effects of transformation twin on Hall-Petch relationship in Mn-Cu alloy[J].Materials science&engineering A,2008,492(1-2):419-427.
[11]SONG Y Q,LI S C.Sintering feature of Cu and Mn metallic powders[J].Journal of the University of Petroleum,China,2001,25(5):76-78.
[12]FUKUHAR A M,YIN F,OHSAW A Y,et al.High damping propeties of Mn-Cu sintered alloys[J].Materials science,2006,442(1-2):439-443.