退火态增材制造AZ91D镁合金在极端条件下的力学行为  

Mechanical behavior of additively manufactured AZ91D magnesium alloy with annealing state under extreme conditions

作　　者：甘志鹏 涂灿[3] 陈剑斌 谢超 王永刚[1,2] 汪小锋 GAN Zhipeng;TU Can;CHEN Jianbin;XIE Chao;WANG Yonggang;WANG Xiaofeng(Faculty of Mechanical Engineering and Mechanics,Ningbo University,Ningbo 315211,China;Key Laboratory of Impact and Safety Engineering,Ministry of Education,Ningbo University,Ningbo 315211,China;The First Affiliated Hospital of Ningbo University,Ningbo 315020,China)

机构地区：[1]宁波大学机械工程与力学学院,宁波315211 [2]宁波大学冲击与安全工程教育部重点实验室,宁波315211 [3]宁波大学附属第一医院,宁波315020

出　　处：《中国有色金属学报》2024年第4期1268-1284,共17页The Chinese Journal of Nonferrous Metals

基　　金：宁波市科技创新2025重大专项项目(2021Z099,2020Z042);国家自然科学基金资助项目(52005271);新金属材料国家重点实验室开放基金资助项目(2023-Z04)。

摘　　要：本研究使用激光选区熔化技术(Selective laser melting,SLM)制备了AZ91D镁合金(SLM-AZ91D),并对其进行去应力退火处理,采用微观组织表征与力学特性测试研究了退火态SLM-AZ91D镁合金在不同温度与应变速率等极端条件下的力学行为。结果表明:退火态SLM-AZ91D试样中主要包含α-Mg基体、β-Mg_(17)Al_(12)等相,不同区域的蜂窝结构存在明显差异,平均晶粒尺寸非常细小,仅为1.82μm,无明显织构;相较于打印态试样,退火态试样的平均显微硬度值提升了约26.7%;退火态试样的压缩流变应力在173~293 K时对温度不敏感,而在373~573 K时则表现出显著的温度软化效应;随着温度的升高,流变应力呈现下降趋势。尽管应变速率强化效应较弱,但退火态试样的流变应力仍随着应变速率的增大而逐渐增大。基于实验结果拟合了修正Johnson-Cook本构模型,该模型的计算结果与实验结果吻合较好。In this study,an AZ91D magnesium alloy was prepared by selective laser melting(SLM)and annealed subsequently.The mechanical behavior of annealed AZ91D magnesium alloy under extreme conditions such as different temperatures and different strain rates,was studied by microstructure characterization and mechanical property testing.The results show that the annealed SLM AZ91D sample mainly contains an α-Mg matrix,β-Mg_(17)Al_(12) and other phases,and the honeycomb structure in different regions is obviously different.The average grain size is very fine,only 1.82μm,with no obvious texture.Compared with the printed sample,the average microhardness of the annealed sample increases by approximately 26.7%.Compressive flow stress is insensitive to temperature from 173-293 K,but shows a significant temperature softening effect from 373−573 K.With the increase of temperature,the flow stress shows a downward trend.Although the strain rate strengthening effect is weak,the flow stress still increases with increasing strain rate.Based on the experimental results,the modified Johnson-Cook constitutive model is fitted,which is in good agreement with the experimental results.

关 键 词：选区激光熔化 AZ91D镁合金 微观组织 力学行为 修正的Johnson-Cook本构模型 

分 类 号：TG146.22[一般工业技术—材料科学与工程]