摘要
利用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、X射线衍射仪(XRD)和力学试验机等研究了铸造Mg-6Zn-2.5Cu合金在铸态、固溶和时效处理下的显微组织和力学性能。结果表明:合金的铸态组织主要由α-Mg和(α-Mg+MgZn2+Mg2Cu+CuZnMg)共晶相组成。在455℃固溶12~36 h时,随着时间增加,固溶效果逐渐增强,且在20 h时合金获得了较理想的显微组织及218 MPa的抗拉强度和8.68%的伸长率。随后在180℃时效6~72 h后,合金的拉伸性能随时效时间的增加呈先增加后减小的趋势,其中时效24 h时后,合金的抗拉强度和硬度达到峰值,分别为249.5 MPa和64.6 HV0.1,比铸态的分别提高了66.5 MPa和26.29%,伸长率在时效12 h时后达到了峰值6.72%。铸态合金的断裂方式以沿晶断裂为主,时效处理后合金的断裂方式为准解理断裂。
Microstructure and mechanical properties of Mg-6 Zn-2.5 Cu alloy under as-cast, solid solution and aging treatment were studied by means of optical microscope(OM), scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffractometer(XRD) and mechanical testing machine. The results show that the microstructure of the as-cast alloy is mainly composed of α-Mg and(α-Mg+MgZn2+Mg2Cu+CuZnMg) eutectic phase. After solid solution treatment at 455 ℃ for 12-36 h, the solid solution effect is gradually enhanced with the increase of solution time, and after solid solution treatment at 455 ℃ for 20 h, the microstructure of the alloy is optimal, the tensile strength and the elongation are 218 MPa and 8.68%,respectively. After aging at 180 ℃ for 6-72 h, the tensile properties of the alloy increase at first then decrease with the increase of aging time. After aging for 24 h, the tensile strength and the hardness of the alloy reach the peak value of 249.5 MPa and 64.6 HV0.1, respectively, which are 66.5 MPa and 26.29% higher than those of the as-cast alloy, and the maximum value of elongation of the alloy is 6.72% after aging at 180 ℃ for 12 h. The fracture mode of the as-cast alloy is mainly intergranular fracture, and the fracture mode of the alloy after aging treatment is quasi-cleavage fracture.
作者
张玉
李明
杨文龙
王宗刚
王学志
ZHANG Yu;LI Ming;YANG Wen-long;WANG Zong-gang;WANG Xue-zhi(College of Physics and Electromechanical Engineering,Hexi University,Zhangye 734000,China;Institute of Advanced Material Forming Tech no logy,Hexi University,Zhangye 734000,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2020年第4期40-46,共7页
Transactions of Materials and Heat Treatment
基金
河西学院博士科研启动基金
河西学院校长基金(XZ2018014)。
