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摘要：
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研究了二次加热工艺参数对SIMA法制备7A04合金半固态触变组织的演化规律。结果表明:随着加热温度的升高和保温时间的延长,晶粒的形状逐渐趋于球形。当加热温度低于610℃时,晶粒尺寸不断长大,而后逐渐减小。在保温的初始阶段,共晶液相没有完全浸润晶粒边界,晶粒的聚结长大处于主导地位。当保温时间达到4 min左右时,共晶液相几乎充满了所有的晶界,Ostwald长大扩散机理处于主导地位。晶粒长大规律符合动力学方程。
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The thixotropic microstructural evolution's law of reheating parameters on 7A04 alloy by SIMA method was studied.The results show that the grain shape approaches to sphericity slowly with the increasing of heating temperature and soaking time.The grain sizes grow up when the heating temperature is lower than 610 ℃,and then decrease slowly.At the initial stage of soaking,eutectic liquid is not distributed between the whole primary grains,so the main mechanism of grain coarsening is coalescence.When the soaking time reaches up to 4 min,eutectic liquid nearly fills out all grain boundaries and the main mechanism of grain coarsening is Ostwald ripening instead of coalescence.Moreover,the mechanism of grain coarsening belongs to volume diffusion during isothermal process and is satisfied with dynamic equation.
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基金项目：
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江苏省高校自然科学基础研究项目资助(07KJD460007);;
常州工学院自然科学研究项目资助(YN06043)
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作者简介：
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参考文献：
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[1]Jung B I,Jung C H,Han T K.Electromagnetic stirring andsr modification in A356 alloy[J].J.Mater.Process.Tech.,2001,111(1-3):69-73.
[2]徐俊,田战峰,石力开,等.半固态铝合金设计与试验研究[J].稀有金属,2004,28(2):358-361.
[3]罗守靖,姜巨福,杜之明.半固态金属成形研究的新进展、工业应用及其思考[J].机械工程学报,2003,39(11):52-60.
[4]吉泽升,李庆芬,刘兆晶,等.应变诱发AZ91D镁合金半固态组织形态及形成机理[J].中国有色金属学报,2003,13(5):1156-1160.
[5]Wu S S,Wu X P,Xiao Z H.A model of growth morphology forsemi-solid metals[J].Acta Materialia,2004,52:3519-3524.
[6]Kim N S,Kang C G.An investigation of flow characteristics con-sidering the effect of viscosity variation in the thixoforming process[J].J.Mater.Process.Tech.,2000,103:237-246.
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