刘筱,朱必武.高速冲击载荷下LZ91镁合金的动态变形行为及力学本构[J].稀有金属材料与工程,2019,48(7):2171~2178.[Liu Xiao,Zhu Biwu.The dynamic deformation behavior and mechanical constitutive of LZ91 magnesium alloy under high speed impacting[J].Rare Metal Materials and Engineering,2019,48(7):2171~2178.]
高速冲击载荷下LZ91镁合金的动态变形行为及力学本构
投稿时间:2018-03-06  修订日期:2018-04-14
中文关键词:  LZ91镁合金  绝热剪切  织构  Burgers取向关系  Johnson-Cook 本构方程
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目),
中文摘要:
      采用金相显微镜、X射线衍射结合斯密特因子研究高速冲击载荷下LZ91镁合金的动态变形行为和力学本构。结果表明:流变应力对应变速率不敏感,发生了Portevin-LeChatelier效应;当应变速率为3600s-1时才出现绝热剪切带,这是由于β-Li相间细小均匀分布的α-Mg相增大了位错运动阻力,导致绝热剪切敏感性减弱;α-Mg相形成了偏离基面织构20~30°的特殊织构,不需要孪生来协调均匀塑性变形,这是因为α/β相界面取向接近Burgers取向关系;修正了Johnson-Cook力学本构,拟合结果与实验结果吻合。
The dynamic deformation behavior and mechanical constitutive of LZ91 magnesium alloy under high speed impacting
英文关键词:LZ91 magnesium alloy  Adiabatic shear  Texture  Burgers orientation relationship  Johnson-Cook constitutive equation
英文摘要:
      The dynamic deformation behavior and mechanical constitutive of LZ91 magnesium alloy were investigated under high speed impacting using optical microscopy and X-Ray diffraction combing with Schmid factor. The results show that the flow stresses are not sensitive to strain rate and the Portevin-LeChatelier effect occurs. The fine α-Mg phase uniformly distributes in β-Li phase, causing that the dislocation motions are hindered. This finally induces that the adiabatic shear sensitivity decreases and the adiabatic shear band only occurs above 3600s-1. The special texture, which deviates the basal texture nearly 20-30°, in α-Mg phase forms, due to the Burgers orientation relationship between α/β phase interface. Twinning is not required to accommodate the uniform plastic deformation in α-Mg phase because of this orientation relationship. The Johnson-Cook (J-C) mechanical constitutive was modified and the fitting results well match with the experimental results.
作者单位E-mail
刘筱 湖南科技大学材料科学与工程学院 liuxiao0105@163.com 
朱必武 湖南科技大学 高温耐磨材料及制备技术湖南省国防科技重点实验室  
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