摘要
采用光学显微镜对挤压态AZ61镁合金的显微组织进行了观察,利用Hopkinson杆杆测试技术对挤压态AZ61镁合金进行了高应变速率冲击拉伸试验,测定了该合金在不同应变速率下的完整动态应力-应变曲线;对该合金在高应变速率下动态应力-应变行为及其应变速率对挤压态AZ61镁合金的屈服行为及其断裂机制的影响进行了分析。结果表明,在整个加载过程中,材料的弹性模量变化很小;在拉伸过程中,该材料表现出明显的屈服点。随着应变速率的增加,材料的抗拉强度相应增大,失稳应变相应减小,但表现出的应变速率强化效应不明显。采用SEM对其断口进行分析,结果表明挤压态AZ61镁合金拉伸断口对应变速率不敏感,表现为以韧性为主伴有少量解理特征的混合断裂。
Microstructure of as-extruded AZ61 magnesium alloy was observed by optical microscope(OM),and high strain impacting testing for the alloy was carried out by the Hopkinson bar to map the stress-strain curves at different strain rate.Dynamic stress-strain behavior of the as-extruded alloy was analyzed at high strain rate,and effects of strain rate on yield strength and crack mechanism were described.The results reveal that elastic modulus of the alloy exhibits somewhat change in the whole loading process,while obvious yield point can be observed in tensile testing.With increasing in strain rate,tensile strength of the alloy is increased with decreasing in mestable strain,however,absence of strain rate strengthening effects can be observed.The fracture morphology of the alloy was observed by SEM(scanning electron microscope).It is found that tensile crack morphology of the as-extruded magnesium alloy is characterized by ductile fracture accompanying with a little cleavage fracture,showing the non-sensitivity for the strain rate.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2009年第6期501-504,共4页
Special Casting & Nonferrous Alloys
基金
重庆市科技攻关项目(CSTC2007AA4008)
关键词
镁合金
力学行为
应变速率
断口
Magnesium Alloy,Mechanical Behavior,Strain rate,Fracture
