摘要
采用光学显微镜(OM)、X射线衍射仪(XRD)、扫描电镜(SEM)等对Mg-4Y-2Sm-1Gd-0.5Zr合金的微观组织及物相进行了分析,并采用拉伸实验机在不同温度下对其进行了力学性能测试。结果表明:Mg-4Y-2Sm-1Gd-0.5Zr合金的铸态组织主要由α-Mg基体和Mg_(24)Y_5,Mg_(41)Sm_5和Mg_5Gd相组成,经过固溶处理后,稀土元素大部分被固溶进基体形成过饱和固溶体;Mg-4Y-2Sm-1Gd-0.5Zr合金的最佳热处理工艺为525℃×10 h+225℃×12 h,此时合金的抗拉强度、屈服强度和伸长率分别为223.6 MPa、146.5 MPa和14.1%,表明合金具有较高的强度和良好的塑性,综合力学性能优异,其强化机制主要是析出强化;时效态Mg-4Y-2Sm-1Gd-0.5Zr合金在150～250℃范围内强度变化不明显,性能稳定,特别适合在150～250℃服役条件下使用。随拉伸温度的升高,合金的断裂方式由脆性解理断裂向微孔聚集型韧性断裂转变。
Microstructure and phase of Mg-4Y-2Sm-1Gd-0.5Zr alloy were analyzed by means of optical microscope,X ray diffractometer and scanning electron microscopy,and mechanical properties of the alloy were tested by tensile test machine at different temperatures.The results show that the as-cast microstructure of the Mg-4Y-2Sm-1 Gd-0.5Zr alloy is mainly composed of α-Mg matrix,Mg24Y5,Mg41 Sm5 and Mg5 Gd phases.After solid solution treatment,most of the rare earth elements are dissolved into the matrix to form supersaturated solid solution.The optimum heat treatment process of the Mg-4Y-2Sm-1Gd-0.5Zr alloy is solid solution at 525℃ for 10 h and then aging at 225℃ for 12 h,the tensile strength,yield strength and elongation of the alloy are 223.6 MPa,146.5 MPa and 14.1%,respectively, which show that the alloy has high strength,good plasticity and excellent comprehensive mechanical properties,and its strengthening mechanism is mainly precipitation strengthening.The aging Mg-4Y-2Sm-1Gd-0.5Zr alloy has no obvious change in strength in the range of 150-250℃ ,and its performance is stable,so it is especially suitable for service at 150-250℃.With the increase of tensile temperature, the fracture mode of the alloy changes from brittle cleavage fracture to microporous aggregate ductile fracture.
作者
李志涛
李全安
陈晓亚
LI Zhi-tao;LI Quan-an;CHEN Xiao-ya(School of Materials Science and Engineering,Henan University of Science and Technology,Luoyang 471023, China;Collaborative Innovation Center of Nonferrous Metals,Henan Province,Luoyang 471023,China;School of Materials Science and Engineering,Xi'an University of Technology,Xi'an 740048,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2018年第12期1-7,共7页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51571084
51171059)
河南省重点科技攻关计划资助项目(152102210072)
