表面机械研磨处理对热轧态Mg-Gd-Y合金微观组织和力学性能的影响  

Effect of Surface Mechanical Attrition Treatment on the Microstructure and Mechanical Properties of Hot-Rolled Mg-Gd-Y Alloy

作　　者：宁江利 苑潇逸 吴蒙 陶世洁 李欣康 李旭东 Ning Jiangli;Yuan Xiaoyi;Wu Meng;Tao Shijie;Li Xinkang;Li Xudong(Discipline of Key Materials for Defense Industry,College of Metallurgy and Energy,North China University of Science and Technology,Tangshan 063210,China;Key Laboratory of Modern Metallurgy of the Ministry of Education,Tangshan 063210,China)

机构地区：[1]华北理工大学冶金与能源学院军用关键材料国防特色学科,河北唐山063210 [2]现代冶金技术教育部重点实验室,河北唐山063210

出　　处：《稀有金属材料与工程》2022年第2期566-572,共7页Rare Metal Materials and Engineering

基　　金：国防基础科研项目(JCKY2018407C008);华北理工大学杰出青年基金(JQ201702)。

摘　　要：镁合金由于塑性变形能力较差,采用热轧制备板材时由于工艺限制往往使晶粒组织粗大,导致力学性能不佳。采用表面机械研磨处理(SMAT)在热轧态Mg-Gd-Y合金中获得梯度组织,以提高合金的强韧性并揭示相关机理。热轧态合金在峰时效之后,强度显著上升但塑性急剧下降,这是因为沉淀相容易在粗晶内引起应力集中,诱发解理开裂、造成脆性断裂。SMAT试样在峰时效之后,强度相当而塑性增加,显示了较好的强韧性。这是因为表面细晶层由于均匀变形能力较好导致延性断裂,阻碍了试样内部粗晶层解理开裂对试样截面的贯穿,从而抑制了早期开裂,使塑性得以提升。Due to the poor deformability of Mg alloys, the processing parameters for hot-rolling are restricted. This generally results in microstructures characterized by coarse grains, accompanied by inferior mechanical properties. To enhance the toughness, surf ace mechanical attrition treatment(SMAT) was utilized in this work to produc e gradient structure in a hot-rolled(HR) Mg-Gd-Y alloy. The underlying mechanisms for toughening were disclosed. After peak-ageing(PA), the strength of the HR alloy increases obviously while the ductility decreases sharply. This is because the precipitates block dislocations and generate stress concentration, resulting in cleavage fracture as a brittle rupture. The HR-SMAT-PA sample shows comparable strength with the HR-PA sample, while the ductility is enhanced,exhibiting better toughness. The ultrafine grains in the near-surface layer lead to uniform deformation and ductile fracture. Thus, the cleavage fracture in the deep layer could not go through the entire cross-section of the sample. As a result, the premature failure is inhibited and the ductility is increased.

关 键 词：镁合金 强韧性 梯度组织 脆性断裂 延性断裂 

分 类 号：TG146.22[一般工业技术—材料科学与工程]