T6热处理对多向锻态VWZ113K稀土镁合金微观组织及力学性能的影响  

Effect of T6 heat treatment on microstructure and mechanical properties of multi-directionally forged VWZ113K rare earth Mg alloy

作　　者：车鑫 段兴旺[1] 江东 辛向前 谈芸芸 CHE Xin;DUAN Xing-wang;JIANG Dong;XIN Xiang-qian;TAN Yun-yun(College of Materials Science and Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China)

机构地区：[1]太原科技大学材料科学与工程学院,山西太原030024

出　　处：《塑性工程学报》2024年第5期198-207,共10页Journal of Plasticity Engineering

基　　金：山西省基础研究计划项目(202103021223298,202203021211191)。

摘　　要：以多向锻造Mg-11Gd-3.6Y-2Zn-0.6Zr稀土镁合金为研究对象,利用扫描电镜、能谱分析、电子背散射衍射技术及室温拉伸实验分析了T5和T6热处理工艺对多向锻态稀土镁合金组织和力学性能的影响规律。结果表明,T5热处理后合金为混晶组织,晶界分布有大尺寸长周期堆垛有序(LPSO)结构强化相,合金的屈服强度、抗拉强度及伸长率分别为241 MPa、357 MPa及13.0%;在T6热处理中,随着固溶温度的升高,静态再结晶逐渐形核并长大,促进了组织均匀性提升;但晶粒长大会消耗位错并降低位错强化效应;同时,升温加速了LPSO结构强化相回溶,晶界LPSO结构强化相变得更加细小弥散,促进了弥散强化作用;此外,固溶温度升高还会导致晶粒择优长大,促进织构强化;430℃、8 h+225℃、16 h是最佳热处理工艺,合金的屈服强度、抗拉强度及伸长率分别可达302 MPa、398 MPa及11.5%;多种强化机制均衡作用促使合金强塑性协同提升。Taking the multi-directional forged(MDF)Mg-11Gd-3.6Y-2Zn-0.6Zr rare earth Mg alloy as the research object,the influence of T5 and T6 heat treatment processes on the microstructure and mechanical properties of the multi-directionally forged rare earth Mg alloy was analyzed using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),electron backscatter diffraction(EBSD)and tensile experiment at room temperature.The results show that the alloy after T5 heat treatment has mix crystal microstructure,with large-sized long period stacked ordered(LPSO)structure strengthening phases distributed at grain boundaries.The yield strength,tensile strength and elongation of the alloy are 241 MPa,357 MPa and 13.0%,respectively.During T6 heat treatment,as the solid solution temperature increases,static recrystallization gradually nucleates and grows,promoting the improvement of microstructure uniformity.However,grain growth can consume dislocations and reduce dislocation strengthening effects.At the same time,heating accelerates the dissolution of LPSO structure strengthening phase,and the LPSO structure strengthening phases at grain boundaries become finer and more dispersed,promoting the dispersion strengthening effect.In addition,the increase of solid solution temperature can lead to preferential grain growth and promote texture strengthening.430℃,8 h+225℃,16 h is the best heat treatment process,and the yield strength,tensile strength and elongation can reach 302 MPa,398 MPa and 11.5%,respectively.The balancing effect of various strengthening mechanisms promotes the synergistic enhancement of strength and plasticity of alloy.

关 键 词：稀土镁合金 多向锻造 热处理 微观组织 强化机制 

分 类 号：TG146.2[一般工业技术—材料科学与工程]