功率超声对铸造7050合金中显微疏松的影响

Effects of Power Ultrasonic on Micro-porosity in Cast 7050 Aluminum Alloy

通过传振工具杆对铝熔体进行超声振动处理,探讨了不同的超声功率对7050铝合金铸锭中显微疏松形成的影响。结果表明,经超声处理的铸锭,不仅显微疏松明显减少,而且显微疏松的最大尺寸也明显减小。当其他条件相同,超声功率为200W时,晶粒细化效果最好,超声功率为240W时除气效率最高,当超声功率为240W时,抑制显微疏松形成的效果最佳,铸锭中横截面处显微疏松减少了14.3%～47.9%,中心显微疏松也减小了26.3%～45.0%,这表明超声的细化晶粒和除气作用对抑制显微疏松的形成起了关键作用,而除气起主导作用。此外,工具杆下方的声流效应显著,其对促进液体补缩抑制中心疏松的形成起了积极作用。

Effects of power ultrasonic on micro-porosity in cast 7050 aluminum alloy melt were observed by ultrasonic vibration treatment for aluminum alloy melt with vibration-transfer tool rod.The results reveal that ultrasonic vibration can decrease significantly percentage and size of micro-porosity in the alloy.At given other conditions,grain size is desirable with ultrasonic power of 200 W,and degassing effects is the maximum with ultrasonic power of 240 W.Meanwhile,effects of restraining the micro-porosity formation is the best,where micro-porosity percentage in cross-section is reduced by 14.3%~47.9% and that in central is decreased by 26.3%~45%,which is attributed to grain refinement and degassing effects of ultrasonic treatment,especially degassing effects.In addition,the large-scale acoustic streaming formed under radiator face plays a positive role in restraining central micro-porosity by promoting liquid metal feeding.