摘要
均匀化热处理能够消除合金铸造缺陷,改善成分偏析提升变形能力。利用光学显微镜(OM)、差分扫描量热计(DSC)、X射线衍射(XRD)、扫描电子显微镜(SEM)、能谱分析(EDS)和万能拉伸实验机等手段,研究了不同均匀化时间(2、5、10、15、20 h)和温度(480、500、520℃)对Mg-9Gd-3.5Y-2Zn-0.35Zr合金微观组织和力学性能的影响规律。结果表明,铸态Mg-Gd-Y-Zn-Zr合金主要包括沿晶界呈网状分布的块状Mg5(Gd,Y,Zn)相及片层状长周期堆垛有序结构相(LPSO),粗大的第二相容易引起局部应力集中而引发裂纹萌生,造成了铸态合金较低的力学性能;经均匀化处理后,大量第二相溶入基体,合金的力学性能得到了显著提升,断裂机制也由铸态的脆性断裂转变为塑性断裂,表明材料塑性得到显著提升;合金的最佳均匀化处理工艺为520℃/15 h,其抗拉强度、屈服强度和伸长率分别由铸态的166.2 MPa、130.2 MPa和3.3%提高到213.5 MPa、154.5 MPa和7.6%。
Homogenization treatment can eliminate alloy casting defects,improve composition segregation and enhance deformation ability.The effects of different homogenization time(2,5,10,15,20 h)and temperature(480,500,520℃)on the microstructure and mechanical properties of Mg-9Gd-3.5Y-2Zn-0.35Zr alloy were studied using optical microscope(OM),differential scanning calorimeter(DSC),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy spectroscopy analysis(EDS)and universal tensile experimental machine and other means.The results show that the as-cast Mg-Gd-Y-Zn-Zr alloy mainly includes a blockMg5(Gd,Y,Zn)phase distributed in a network along the grain boundary and lamellar long-period stacking ordered(LPSO)phases,the coarse second phase easily cause local stress concentration and crack initiation,resulting in lower mechanical properties of the as-cast alloy.After homogenization treatment,large amounts of second phase are dissolved into thematrix,themechanical properties of the alloy are significantly improved,the fracturemechanismalso changes froma caststate brittle fracture to a plastic fracture,indicating that the material plasticity is significantly improved.The optimum homogenization process is 520℃/15 h,and the tensile strength,yield strength and elongation of the alloy are increased from 166.2 MPa,130.2 MPa and 3.3%to 213.5 MPa,154.5 MPa and 7.6%,respectively.
作者
刘凯
陈伟
谢家松
杨晓禹
王红杰
祁泽星
陈刚
张星
LIU Kai;CHEN Wei;XIE Jiasong;YANG Xiaoyu;WANG Hongjie;QI Zexing;CHEN Gang;ZHANG Xing(Inner Mongolia Metallic Materials Research Institute,Ningbo 315103,China;Jiang Shan Heavy Industries Research Institute Co.,Ltd.,Xiangyang 441057,China;Key Laboratory of Ningbo Surface Engineering Center,Zhejiang,Ningbo 315103,China;School of Materials Science and Engineering,North University of China,Taiyuan 030051,China)
出处
《热加工工艺》
北大核心
2023年第4期139-143,149,共6页
Hot Working Technology
基金
宁波市2025重大科技攻关项目(2020Z108)。
作者简介
刘凯(1994-),男,黑龙江五大连池人,硕士研究生,主要研究方向:金属金属精密成形及热处理,电话:19834407677,E-mail:752611164@qq.com;通讯作者:杨晓禹(1989-),男,山东烟台人,博士后,主要从事轻合金精密加工技术研究,E-mail:yangxiaoyuguoying@foxmail.com。
