Surface quality study of AZ31B Mg alloy in electric pules-ultrasonic assisted incremental sheet forming
Surface quality study of AZ31B Mg alloy in electric pules-ultrasonic assisted incremental sheet forming
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DOI：
10.1007/s00170-022-10037-1
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
Zimo Song;Haoran Zhang;X. Chu;Z. Zhao;Jun Gao
中科院分区：
文献类型：
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作者：
Zimo Song;Haoran Zhang;X. Chu;Z. Zhao;Jun Gao
表面质量差是制约镁合金成形和应用的主要问题之一。本文将电脉冲和超声振动同时应用于镁合金板材渐进成形过程中，研究了电脉冲-超声复合能量场对成形表面质量的影响。与电脉冲辅助成形相比，在较高的电流频率(≥ 350HZ)、较小的台阶深度(0.10 mm)下，复合能场可以在任何条件下减小成形力，改善表面质量，并保持有效电流密度小于30A/mm~2。成形力和表面粗糙度的最大下降百分比分别约为20%和50%。此外，虽然超声能量在两个方向上都能改善表面质量，但垂直于进给方向的影响比平行于进给方向的影响更显著。超声振动引起的反复滚动有利于表面沟槽的重新排列，使表面轮廓高度分布相对均匀。在高电流密度条件下，由于超声振动的动态冲击和过高的温度升高引起的表面严重氧化，也会使表面质量恶化。
Poor surface quality is one of the main problems for the forming and application of magnesium alloys. In this study, electric pulse and ultrasonic vibration were simultaneously applied to the incremental sheet forming (ISF) process of magnesium alloys, and the effect of electric pulse–ultrasonic composite energy field on the surface quality was investigated. Compared with electric pulse–assisted forming, a composite energy field could reduce the forming force under any condition and improve the surface quality at the condition of higher current frequency (≥ 350 HZ), lower step depth (0.1 mm), and keep the effective current density less than 30 A/mm2. The maximum percentage decrease in forming force and surface roughness is about 20 and 50%, respectively. Moreover, although the surface quality can be improved by ultrasonic energy in both directions, the effect is more significantly in direction perpendicular to the feed direction than that in the direction parallel to the feed direction. The repeated rolling caused by ultrasonic vibration is benefit to the rearrangement of the surface gully and makes the surface profile height distribution relatively uniform. The surface quality also would be aggravated due to the dynamic impact of the ultrasonic vibration and serious surface oxidative, which caused by excessive temperature increasing at the condition of high current density.