超声处理对7050铝合金凝固组织晶粒细化影响
Effect of Ultrasonic Treatment on Grain Refining of Solidification Microstructure of 7050 Aluminum Alloy
胡仕成, 张 平, 李 建, 杨运猛
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作者单位：中南大学 机电工程学院 现代复杂装备设计与极端制造教育部重点实验室, 湖南 长沙 410083
中文关键字：7050铝合金； 功率超声； 细化； 晶粒尺寸； 负指数关系
英文关键字：7050 aluminum alloy; power ultrasound; refining; grain size; negative exponential relation
中文摘要：研究了功率超声对7050铝合金凝固组织晶粒细化规律。实验结果表明，功率超声施振对7050凝固组织有显著细化作用，并随施振功率的增大，晶粒细化效果增强。 但超声施振功率增大到一定程度后，晶粒细化效果不再明显。在铝熔体凝固过程的不同温度区间施加超声振动，温度过高、过低都会减弱细化效果，超声最佳施振温度区间为760～660 ℃。施振功率为240 W时平均晶粒尺寸可达67 μm。对平均晶粒尺寸与超声功率分析表明：超声施振功率与细化晶粒尺寸近似满足负指数递减关系，这为超声细晶技术在工业应用方面提供了实验依据。
英文摘要：The rule of power ultrasound on grain refining of solidification microstructure of 7050 alloy was investigated. The results indicate that solidification microstructure of 7050 alloy was refined significantly by power ultrasonic treatment, with the increase of ultrasonic power, more refined microstructure can be obtained, however, the effect of further refining is not obvious when the ultrasonic power reaches a certain level. The refining effect weakens when the temperature of melt treated by ultrasonic is beyond a certain zone, and an optimal temperature zone for ultrasonic treatment is 760～660 ℃. Average grain size can reach 67 μm when ultrasonic power is 240 W. Based on the analysis on average grain size and ultrasonic power, there is an approximate negative exponential relation between ultrasonic power and average grain size, which provide an experimental basis for industrial apply of ultrasonic fine-grained technology