超声振动辅助微压印成形及其作用机制

Ultrasonic vibration assisted micro⁃coining and its mechanism

进行了不同条件下的超声振动辅助微压印实验,并利用有限元方法分析了实验结果。结果表明,坯料高度较小时,超声振动能够显著提高微圆柱压印高度,最大增幅为350%。微圆柱压印高度随着超声作用时间的增加而增加,但当超声作用时间超过10 s后,材料达到超声振动条件下的成形极限,继续延长超声作用时间不再有明显的作用。超声表面效应使摩擦因数降低了76.4%,对微圆柱压印高度的增长起到主要作用,贡献率为94.8%,超声体积效应使材料流动应力下降了16.8 MPa,对微圆柱压印高度增长的贡献率仅为5.2%。

Ultrasonic vibration assisted micro⁃coining experiments were conducted under different conditions,and the experiment results were analyzed using finite element method.The results show that ultrasonic vibration can significantly increase the micro⁃cylinder coining height with the maximum increase amplitude of 350%when the blank height is small.The micro⁃cylinder coining height increases with the increase of ultrasonic action time,but when the ultrasonic action time exceeds 10 s,the material reaches the forming limit under ultrason⁃ic vibration conditions,and extending ultrasonic action time continuously no longer has significant effect.The ultrasonic surface effect re⁃duces the friction coefficient by 76.4%,which plays a major role in the growth of the micro⁃cylinder coining height with contribution of 94.8%,and the ultrasonic volume effect decreases the material flow stress by 16.8 MPa,which contributed only 5.2%to the growth of the micro⁃cylinder height.