AZ31B-H24镁合金钣金件在多向加载下的力学性能实验研究(英文)

Experimental Study on Mechanical Properties of AZ31B-H24 Magnesium Alloy Sheets under Multi-Axial Loading Conditions

镁合金在汽车轻量化设计中富有前景。基于单向、双向和等双向拉伸的实验数据,本文研究了AZ31B镁合金钣金件的塑性和断裂特性;结果显示:在这两方面,AZ31B有显著各向异性。标定了Hill1948、Barlat1989和Barlat2003的塑性本构模型,结果表明:在应用联合流动法则时,上述模型均不能同时准确地预测不同材料方向下的强度和塑性流动;因此对于这种材料,推荐使用非联合塑性流动法则。可用数字图像相关(DIC)技术和测量断裂处面积收缩技术来得到AZ31B镁合金的断裂应变;可用修正的Mohr-Coulomb断裂准则(MMC)和断裂成形极限图(FFLD)来预测材料断裂。

Since magnesium alloy is a promising engineering material for the automotive light-mass design, this paper investigates the plasticity and fracture properties of AZ31B sheets based on the experimental results from uniaxial, biaxial and equi-biaxial tensions. The results show that AZ31B displays remarkably anisotropy in both plasticity and fracture. Hi11-1948, Barlat-1989 and Barlat-2003 anisotropic constitutive models were calibrated for plasticity. The results show that that none of the above models accurately describes both material strength and plastic flow at various orientations if associated flow rules are assumed. Therefore, non-associated flow is suggested for this material. The ductile fracture strains of AZ31B-H24 can be measured using two methods, the correlation Digital Imaging Correlation （DIC） system and the fracture-initiation-locations area-reduction, with the forecast results calculated using the fracture forming limit diagram （FFLD） and the modified Mohr-Coulomb criterion （MMC）.