汽车用6xxx系铝合金薄壁件的韧性断裂行为  

Ductile fracture behavior of 6xxx aluminum alloy thin-walled components of automobile

作　　者：叶拓[1] 王冠[1] 姚再起[2] 李落星[1] 

机构地区：[1]湖南大学汽车车身先进设计制造国家重点实验室,长沙410082 [2]杭州吉利汽车研究院有限公司NVH及材料工程部,杭州311228

出　　处：《中国有色金属学报》2014年第4期878-887,共10页The Chinese Journal of Nonferrous Metals

基　　金：国家"十二五"科技支撑计划资助项目(2011BAG03B02);国家自然科学基金面上资助项目(51075132);长沙市科技重大专项(K1204008-11-1);湖南大学汽车车身先进设计与制造国家重点实验室自主课题资助项目(61075005)

摘　　要：针对汽车用6xxx铝合金薄壁件,采用准静态拉伸实验获得材料的真实应力—应变曲线,通过线性回归拟合的方法得到6061和6063材料的Johnson-Cook本构参数A、B、n值分别为90 MPa、422.58 MPa、0.5234和60 MPa、323.57 MPa、0.428。为了准确地预测铝合金变形过程中的开裂行为,将Crockroft-Latham韧性断裂准则引入到数值模拟中,计算出6061和6063铝合金材料的韧性断裂常数分别为334.09 MPa和309.79 MPa。对铝合金缺口试样拉伸实验和汽车铝合金薄壁件压缩实验进行数值模拟和实验验证,发现试样的力和位移曲线以及断裂位置与仿真预测结果吻合度较高,该方法能够方便、准确地预测两种铝合金材料薄壁件的开裂行为。在实际的工程应用中,该方法成为判断材料的断裂失效的一种有效的方法。The true stress-strain curve of automobile 6xxx aluminum alloy thin-walled components was obtained by tensile tests. Johnson-Cook constitution parameters of aluminum alloys 6061 and 6063 were analyzed by means of linear regression analysis method, the values ofA,B,n of each alloy are 90 MPa, 422.58 MPa, 0.5234 and 60 MPa, 323.57 MPa, 0.428, respectively. In order to estimate the fracture behavior of aluminum alloy during the deformation, Crockroft- Latham ductile damage criterion was incorporated into the numerical simulation. The calculated ductile fracture parameters of 6061 and 6063 aluminum alloys are 334.09 MPa and 309.79 MPa. Simulation approach was employed to predict the fracture of notched sample tensile tests and compression tests of thin-walled aluminum components. The numerical results, such as load-displacement curves and fracture position, are in good agreement with experimental measurements. This method, which provides a valid way to forecast the fracture of material in engineering application, can be used to predict fracture behavior of thin-walled aluminum alloy with satisfactory convenience and accuracy.

关 键 词：铝合金 薄壁件 韧性断裂 数值模拟 

分 类 号：TG146.21[一般工业技术—材料科学与工程]