超声辅助镦挤塑性成形过程材料变形模式研究  

Study on Metal Forming Patterns of the Ultrasonic Vibration Assisted Upset-extruding Process

作　　者：吴欣[1,2] 王志海 杨世锡 李峰[3] 沈国强 

机构地区：[1]杭州电子科技大学机械工程学院,杭州310018 [2]浙江大学机械工程学院,杭州310027 [3]宁波双林汽车部件股份有限公司,宁波315613

出　　处：《机械工程学报》2017年第18期71-78,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51475130);中国博士后基金(2013M541769);浙江省自然科学基金(LY14E050025)资助项目

摘　　要：从材料塑性变形的角度,结合试验和应力波理论,研究超声效应对于材料变形的影响规律,提出超声辅助镦挤过程中的材料变形模式。基于镦挤试验,研究材料铝的小孔填充能力和径向变形规律,试验结果表明超声辅助振动可以大幅提高小孔的填充能力和接触区域的径向变形量。利用扫描电镜测试手段,研究了镦挤成形工件的表面形貌,发现超声辅助塑性成形零件表面生成了高硬度的氧化铝膜。归纳总结超声辅助塑性变形过程中的变形模式,基于材料变形等效的原则,结合应力波理论和冲击动力学方法,认为超声辅助镦挤过程中的变形模式与材料塑性模量下降、接触区域摩擦因子下降和超声振动的间歇冲击有关。The ultrasonic vibration effects of the ultrasonic vibration assisted forming process are studied from the view of metal plastic deformation patterns. First, the small-hole filling capacity and radial flow rules are studied for the upset-extruding process. Experimental results show that the ultrasonic vibration can increase not only the length of extruded cylinder but also the radial deformation. The surface morphology of the deformed workpiece are studied by using scanning electron microscope, the data shows that the black material covered the workpiece surface is Al2O3. The metal deformation patterns of the ultrasonic vibration assisted forming process are proposed based the experimental observation. The cause of these metal deformation patterns are considered to have connections with the decrease of plastic modulus, improvement of frictional condition along workpiece-tool interface and intermittent impact of ultrasonic vibration.

关 键 词：超声效应 镦挤 变形模式 

分 类 号：TG376[金属学及工艺—金属压力加工]