形变热处理对Mg-4Al-1Si-1Gd合金组织及性能的影响  

Effect of Deformation Heat Treatment on Microstructure and Properties of Mg-4Al-1Si-1Gd Alloy

作　　者：朱奕瑶 冯俊强 张增耀[1] 杨哲宁 张向鹏 王红霞[1] ZHU Yiyao;FENG Junqiang;ZHANG Zengyao;YANG Zhening;ZHANG Xiangpeng;WANG Hongxia(College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China;School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China;Shanxi Jiangyang Chemical Co.,Ltd.,Taiyuan 030041,China)

机构地区：[1]太原理工大学材料科学与工程学院,太原030024 [2]天津大学材料科学与工程学院,天津300350 [3]山西江阳化工有限公司,太原030041

出　　处：《材料导报》2021年第20期20149-20154,共6页Materials Reports

基　　金：山西省重大专项资助项目(20191102008,20191102007);山西省大学生创新创业项目(2018093);山西省镁基材料电脉冲辅助成形科研设施与仪器共享服务平台项目(201805D141005);山西省专利推广实施资助专项(20200718)。

摘　　要：为改善Mg-Al-Si系(AS系)变形镁合金因第二相粗大、分布不均而性能较低的现状,在200℃下对挤压态Mg-4Al-1Si-1Gd合金分别进行不同时间(5 h、10 h、15 h)的等温时效和等通道挤压(ECAP)处理,并利用光学显微镜、扫描显微镜和拉伸实验分析其组织及拉伸性能。结果表明:随着等温时效时间的延长,晶粒尺寸增大,晶界处析出少量聚集的大尺寸Mg_(17)Al_(12)相,时效10 h后合金的室温拉伸性能较优,但与挤压态相比强塑性明显降低。而形变时效提供的热变形能和应变累积量促进了动态再结晶的充分进行,晶粒尺寸由挤压态的10.68μm减小至2.20μm,Mg 2Si相和Si_(3)Gd_(5)相碎化完全且分布更均匀,晶界处析出了大量颗粒状Mg_(17)Al_(12)相,基面织构明显弱化,形成了新的非基面织构组分,抗拉强度、屈服强度和延伸率与挤压态相比分别提高了11.7%、33.7%和19.9%。经计算,细晶强化对屈服强度的贡献值为42.8 MPa,Orowan强化的贡献值为4.25 MPa。In order to improve the low performance of AS series wrought magnesium alloy due to the coarse and uneven distribution of the second phase,the extruded Mg-4Al-1Si-1Gd alloys were treated by isothermal aging at 200℃ for 5 h,10 h and 15 h respectively and equal channel angular pressing(ECAP),the microstructure and tensile properties were analyzed by optical microscope,scanning microscope and tensile test.The results show that with the extension of the isothermal aging time,the grain size increases,and a small amount of large-scale Mg_(17)Al_(12) phase is precipitated at the grain boundaries.After aging for 10 h,the tensile properties of the alloy at room temperature were better,but the strength and plasticity of the alloy were obviously lower than that of extruded state.The thermal deformation energy and strain accumulation provided by deformable aging promote the full progress of dynamic recrystallization.The grain size was reduced from 10.68μm in the extruded state to 2.20μm.The Mg 2Si and Si_(3)Gd_(5) phases were fragmented completely and distributed more uniformly,a large number of granular Mg_(17)Al_(12) phases were precipitated at the grain boundary,the basic plane texture was weakened obviously,and a new non-basic plane texture component was formed.The tensile strength,yield strength and elongation of Mg_(17)Al_(12) were increased by 11.7%,33.7%and 19.9%,respectively.The contribution of fine grain strengthening to yield strength was 42.8 MPa,and that of Orowan strengthening was 4.25 MPa.

关 键 词：Mg-4Al-1Si-1Gd合金 形变时效 显微组织 室温拉伸性能 

分 类 号：TG166.4[金属学及工艺—热处理]