不同工艺状态下AZ31B镁合金热压缩变形行为  

Deformation Behavior of AZ31B Magnesium Alloys with Different Process States under Thermal Compression

作　　者：周洁 吴任东[2,3] 袁朝龙 焦玮[2,3] 李滔 Zhou Jie;Wu Rendong;Yuan Chaolong;Jiao Wei;Li Tao(Tsinghua University,Beijing 100084,China;Key Laboratory for Advanced Material Processing Technology,Ministry of Education,Beijing 100084,China)

机构地区：[1]清华大学机械工程系,北京100084 [2]先进成形制造技术教育部重点实验室,北京100084 [3]清华大学,北京100084

出　　处：《稀有金属材料与工程》2020年第5期1793-1798,共6页Rare Metal Materials and Engineering

摘　　要：镁合金在热加工过程中的变形机制复杂,且容易受到材料初始工艺状态和变形条件影响,因此呈现出不同的应力应变关系。采用铸态和变形态的AZ31B作为研究对象,通过Gleeble-1500获取坯料的应力应变曲线随温度和应变率的变化关系,基于Arrhenius双曲正弦型函数构建2种不同工艺状态下镁合金的本构模型,分析初始加工状态对镁合金应力应变关系及变形机制的影响。结果表明:当应变速率大于0.1 s-1,变形态镁合金在低温下由于变形织构及大量孪生产生而出现45°剪切断裂;在高温和低应变速率下2种工艺状态的镁合金变形机制相同,应力应变曲线基本相似;变形态镁合金的硬化指数n及变形激活能Q相比铸态镁合金更低。Deformation mechanism of magnesium alloys is complex and prone to be affected by initial process states and deformation conditions of materials during the thermal process;thus it exhibits different stress-strain relationships.Stress-strain curves of cast and wrought magnesium alloys AZ31B were obtained by Gleeble-1500,and the constitutive models of magnesium alloys under two different initial process states were constructed based on the Arrhenius hyperbolic sine function.The effect of initial process states on stress-strain curves and deformation mechanism of magnesium alloy were analyzed.Results show that shear fracture appears in wrought magnesium alloy along 45°direction due to deformation texture and a large amount of twins at low temperature when the strain rate is greater than 0.1 s-1.However,the deformation mechanisms of cast and wrought magnesium alloys AZ31B keep the same at high temperatures and low strain rates.Therefore,the stress-strain curves of them are basically similar.The hardening index n and activation energy Q of wrought magnesium alloys are smaller than those of cast magnesium alloys.

关 键 词：应力应变曲线 镁合金AZ31B 初始工艺状态 本构方程 

分 类 号：TG146.22[一般工业技术—材料科学与工程]