柱状晶生长取向对定向凝固Mg-Gd合金拉伸和压缩性能的影响  

Effect of growth orientation of columnar crystals on tensile and compressive properties of directionally solidified Mg-Gd alloy

作　　者：连永强 房大然 张航 林小娉 张金玉 郑哲浩 LIAN Yongqiang;FANG Daran;ZHANG Hang;LIN Xiaoping;ZHANG Jinyu;ZHENG Zhehao(School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;School of Resources and Materials,Northeastern University at Qinhuangdao,Qinhuangdao 066004,China)

机构地区：[1]东北大学材料科学与工程学院,沈阳110819 [2]东北大学秦皇岛分校资源与材料学院,秦皇岛066004

出　　处：《中国有色金属学报》2024年第8期2615-2626,共12页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51775099);河北省自然科学基金资助项目(E2021501019,E2022501001);中央高校基本科研业务费(N2323012)。

摘　　要：利用定向凝固技术,制备了生长取向为〈2110〉的柱状多晶Mg-6.3Gd合金和生长取向为〈3214〉的柱状多晶Mg-8.2Gd合金,并研究加载方式(拉伸、压缩)、柱状晶取向与力学性能之间的相关性。结果表明:拉伸载荷下,〈2110〉取向柱状晶的基面〈a〉滑移Schmid因子(Fs)低于0.051、柱状晶内启动{1011}压缩孪生协调应变,因此,Mg-6.3Gd合金屈服强度较高(为176 MPa),但伸长率仅8%;〈3214〉取向柱状晶的基面〈a〉滑移Fs高于0.46、柱状晶内启动{1012}拉伸孪生协调应变,因此,Mg-6.3Gd合金屈服强度较低(为57 MPa),但伸长率达到22%。压缩载荷下,两种取向合金启动{1121}和{1012}两种拉伸孪生协调应变,具有较高的形变硬化能力,抗压强度(分别为309 MPa和301 MPa)较屈服强度分别提高214 MPa和219 MPa,且具有较高的塑性。Mg-6.3Gd alloy with growth orientation concentrated in〈2110〉and Mg-8.2Gd alloy with growth orientation concentrated in〈3214〉were prepared by directional solidification,and the relation between crystal orientation and mechanical properties under tension load and compression load was studied.For the Mg-6.3Gd alloy subjected to tensile load,the Schmid factor(Fs)of basal〈a〉slip of columnar crystals with〈2110〉orientation is less than 0.051,and{1011}contraction twinning in columnar crystals is activated to coordinate strain,so the alloy has higher yield strength(σs=176 MPa),but the plasticity is only 8%.In the case of the Mg-8.2Gd alloy subjected to tensile load,Fs of basal〈a〉slip of columnar crystals with〈3214〉orientation is higher than 0.46,and{1012}extension twinning in columnar crystals is activated to coordinate strain,thus the Mg-8.2Gd alloy has lower yield strength(σs=57 MPa),but the plasticity is only 22%.Under compression load,both{1121}and{1012}extension twinning are activated in two alloys,and the compressive strength of the two alloys are much greater than their yield strength,showing distinct work hardening.Meanwhile,the two alloys also have good compressive plasticity.

关 键 词：镁合金 柱状晶取向 加载方式 拉伸孪生 压缩孪生 

分 类 号：TG292[金属学及工艺—铸造]