激光间接冲击下钛箔的微成形特性

Micro-forming properties of Ti foil under laser indirect shock

采用具有高应变率加载特征的激光驱动飞片间接冲击微成形技术对钛箔进行了微成形实验,以解决难成形材料的微塑性成形问题。从飞片完整性、工件贴模性以及厚度减薄率等方面探究了该工艺的成形性能。实验中采用微细电火花和曲面研磨技术制造微模具,材料为AISI 1090模具钢,飞片为20μm的钛箔,成形工件为35μm的钛箔。通过KEYENCE VHX-1000C超景深显微系统对飞片和工件进行了观测和分析,结果显示:飞片具有较好的完整性,能够提供均匀的冲击压力;成形后的工件具有良好的表面质量和贴模性。借助冷镶嵌工艺测量了工件的厚度分布,分析了工件厚度减薄率,其最大值为19.8%,最小值为2%,显示工件的厚度分布比较均匀。研究表明:激光间接冲击微成形技术对于难成形材料具有良好的成形效果并且能有效抑制厚度减薄。

The micro-forming experiments of Ti foils were performed under a laser driven flyer indirect shock with high strain load features to overcome the micro-forming problems of difficult deformed materials.The forming properties of Ti foils under the laser indirect shock were explored from three aspects,the integrity of flyer,the fitability and the ratio of thickness to thinning of workpieces.In this experiment,the mold was fabricated by micro Electrical Discharge Machining（micro-EDM）and curved surface grinding.AISI 1090 die steel was used as the material of mold.The Ti foils with the thickness of 20μm were employed as flyers.Furthermore,Ti foils with the thickness of 35μm were used as workpieces.The flyers and workpieces were observed under a KEYENCE VHX-1000 Cdigital microscope.The results indicate that the flyers show good integrity and provides a uniform shock pressure,so that the workpieces with good surface quality and fitability are fabricated.The coldmounted technique was used to characterize the thicknesses of workpieces and to discuss the ratio of thickness to thinning,which shows that the maximum thinning rate is 19.8% and the minimum thinning rate is 2%.The results demonstrate that the workpieces have uniform thickness distribution.The laser indirect shock micro-forming technique has good forming properties on difficult deformed materials and reduces the thickness thinning effectively.