摘要
应用等温半闭式模锻成形了大尺寸AZ80-Ag悬臂梁,利用光学显微镜(OM)、扫描电子显微镜(SEM)、电子背散射衍射(EBSD)、维氏硬度仪及力学性能试验机,系统研究了悬臂梁底部显微组织、织构及力学性能,并利用时效提高了悬臂梁强度。结果表明:等温模锻后,悬臂梁底部大部分晶粒为动态再结晶晶粒及少量变形晶粒,晶粒内部及晶界分布着一些球状Mg17Al12动态析出相;悬臂梁底部在纵向和横向的抗拉强度、屈服强度及伸长率分别为301、179MPa,9.2%和354、186 MPa,12.3%;时效后,悬臂梁底部纵向和横向的强度均提高,而伸长率均下降。变形态纵向试样的屈服强度比横向的稍低,是基面织构在两个方向偏转程度不一致所致,而时效后强度的提升及伸长率的下降与层片状的Mg17Al12相析出密切相关。
Large-size AZ80-Ag cantilever beams were formed by isothermal semi-closed die forging.The microstructure,texture and mechanical properties of the bottom of the cantilever beam were systematically studied by using optical microscope(OM),scanning electron microscope(SEM),electron backscattering diffraction(EBSD),Vickers hardness tester and mechanical property tester.The strength of cantilever beam was improved by aging.The results show that after isothermal die forging,most of the grains at the bottom of the cantilever beam are dynamic recrystallized grains and a few deformed grains,and some spherical Mg17Al12 dynamic precipitates are distributed in the grain and grain boundary.The tensile strength,yield strength and elongation in longitudinal direction and transverse direction at the bottom of the cantilever beam are 301,179 MPa,9.2%,and 354,186 MPa,12.3%respectively.After ageing,the longitudinal and transverse strength of the cantilever beam increases,while the elongation decreases.The yield strength of the longitudinal sample in deformed state is slightly lower than that of the transverse one,which is caused by different degree of deflection of the basic surface texture in both directions,and the increase of strength and the decrease of elongation after aeing are closely related to the precipitation of lamellar Mg17Al12 phase.
作者
刘磊
刘楚明
魏建胜
曾钢
LIU Lei;LIU Chuming;WEI Jiansheng;ZENG Gang(School of Materials and Engineering,Central South University,Changsha 410083,China)
出处
《热加工工艺》
北大核心
2020年第1期29-32,36,共5页
Hot Working Technology
关键词
等温模锻
AZ80-Ag合金
时效处理
织构
力学性能
isothermal semi-closed die forging
AZ80-Ag alloy
ageing treatment
texture
mechanical property
