冲击载荷作用下LPSO结构增强镁-稀土合金变形和损伤机理研究

项目名称： 冲击载荷作用下LPSO结构增强镁-稀土合金变形和损伤机理研究

项目编号： No.51501046

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 冷哲

作者单位： 浙江海洋大学

项目金额： 21万元

中文摘要： 长周期堆垛有序（LPSO）结构增强的镁稀土合金，由于具有高的强度和优异的耐热性能，在汽车、航空航天和武器装备等领域中展现了广阔的应用前景。国内外学者对其在准静态载荷作用下的力学行为、变形和损伤机理已开展了深入研究。然而，关于该材料在冲击加载条件下的研究至今尚未报道。.课题组前期对挤压态Mg-9RY（富钇）-4Zn合金（LPSO结构增强）的动态力学性能进行了初步测定，结果表明该合金具有优异的抗冲击性能。本申请拟以该合金为研究对象，利用分离式霍普金森压杆实验技术，测定其在不同温度及应变速率下的动态力学性能，进而建立动态本构方程；结合材料学微观分析技术，通过对变形后基体中位错、孪晶和LPSO结构的形貌观察及演变分析，阐明合金高应变率下的变形机理；通过对断裂方式、裂纹形成与扩展、绝热剪切变形的研究，揭示合金高应变率下的损伤机理。.本项目可为LPSO结构增强的新型高性能镁稀土合金的设计提供理论支撑。

中文关键词： 高应变速率；变形机理；损伤机理；力学行为；本构关系

英文摘要： Mg-RE alloys strengthened by long period stacking ordered (LPSO) structure, have great potential applications in the fields of automobile, aerospace and weapon industries due to their high strength and excellent heat resistance. Mechanical behaviors, deformation and damage mechanisms of these alloys under quasi static loading conditions have been studied extensively all over the world. However, studies performed under dynamic loading conditions are still lacking until now..The dynamic mechanical properties of the as-extruded Mg-9RY (RY:Y-rich misch metal)-4Zn alloy (strengthened by LPSO structure) were measured preliminarily in our group in the previous studies. The results showed that the alloy exhibited excellent impact resistance. In this proposal, the as-extruded Mg-9RY-4Zn alloy is selected for investigation, its dynamic mechanical properties at various temperatures and strain rates will be measured using Split Hopkinson Pressure Bar experimental techniques, furthermore, its dynamic constitutive relation will be built; Combining with the microstructure analysis techniques of materials science, the deformation mechanisms of the alloy will be studied via morphology observation and evolution analysis of the dislocation, twin and LPSO structure; The damage mechanisms will be revealed based on the investigation into the models of fracture, the formation, propagation of crack and the deformation of adiabatic shear..This study will provide a theoretical basis for designing new high-performance Mg-RE alloys with a LPSO structure.

英文关键词： High strain rate;Deformation mechanism;Damage mechanism;Mechanical behavior;Constitutive relation