7050铝合金冷挤压中心开裂的数值模拟及实验  

Numerical simulation and experiment of internal cracks of 7050 aluminum alloy during cold extrusion

作　　者：余传典 张效迅[1] 马芳[2] 张文丰[1] 吉建莎 喻娟[1] 马凯[1] 

机构地区：[1]上海工程技术大学材料工程学院,上海201620 [2]上海工程技术大学汽车工程学院,上海201620

出　　处：《塑性工程学报》2015年第1期29-33,共5页Journal of Plasticity Engineering

基　　金：上海市高校培养优秀青年教师科研专项基金资助项目(ZZGJD12081)

摘　　要：基于McClintock韧性断裂准则,使用DEFORM2D数值模拟软件模拟剪切摩擦系数、凹模锥角度数、断面收缩率对7050铝合金棒料室温轴对称正挤压过程中内部V型裂纹的萌生和形态转变的影响;参考模拟结果,设计制作正挤压模具,模具工作带角度范围20°-35°,在万能液压机上进行冷挤压实验。数值模拟和实验研究结果表明,摩擦系数在0.05-0.30范围内时,剪切摩擦系数越大,越容易出现V型裂纹向Y型裂纹的转变,且过大的剪切摩擦会抑制中心裂纹的产生;较大的凹模锥角和较小断面收缩率更容易导致中心裂纹的萌生,且断面收缩率对裂纹尺寸的影响很大。Based on McClintock ductile fracture criterion, the DEFORM2D software was used to simulate the effects of shear fric-tion, die cone angle and reduction of area on the initiation and morphology change of V type cracks generated in forward axisym-metric extrusion of 7050 aluminum alloy. According to the results of simulation, the mold with die semitone angles designed from20 to 35 degrees, was made to conduct the cold extrusion on an universal hydraulic machine. Both numerical and experimental re-sults showed that when the friction factor ranged from 0. 05 to 0.3, the greater the shear friction, the higher the possibility forcracks to change shape from V to Y, and excessive shear frictions suppress the central cracking. Large die cone angles and smallreduction of area incur the formation of central cracks, and the reduction of area has a significant influence on crack size.

关 键 词：7050铝合金 数值模拟 冷挤压 内部裂纹 

分 类 号：TG111[金属学及工艺—物理冶金]