针对常规变形方法难以实现的轻合金板成形问题,综合固体颗粒介质成形和超声振动塑性成形技术,提出超声激励颗粒介质成形工艺。采用ABAQUS对变幅杆及凹模按照20 k Hz工作频率进行设计并展开模态及谐响应分析,并以此为基础,设计并制造了最大输出功率1.5 k W的板材超声激励颗粒介质成形模具,进行AZ31B筒形件热态拉深试验,研究超声振动对板材颗粒介质拉深成形的影响。结果表明:超声激励促进颗粒介质的流动性及其传压性能;超声激励影响镁合金板材的极限拉深比,在振幅为6.7~11.6μm范围内,该极限拉深比呈现先增加后降低的规律。超声振动可以降低最佳压边力及成形载荷并抑制法兰区起皱,并且成形载荷随着超声振幅的增加,载荷降低比例越高。
Combining solid granule medium forming technology with ultrasonic vibration plastic forming technology, ultrasonic vibration granule medium forming (UGMF) technology was proposed. To reveal the effect of ultrasonic vibration on flexible-die deep drawing, an ultrasonic vibration with a frequency of 20 kHz and a maximum output of 1.5 kW was on the solid granule medium deep drawing of AZ31B magnesium alloy sheet. The results revealed that ultrasonic vibration promotes the pressure transmission performance of the granule medium and the formability of the sheet. The forming load declines with the ultrasonic amplitude during the drawing process as a result of the combined influence of the "surface effect" and the "softening" of the "volume effect".