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为探索熔体温度处理对自孕育法制备ZA94镁合金半固态坯料组织的细化作用,根据DSC分析结果,设计相应的温度梯度,研究不同熔体处理温度对ZA94镁合金半固态坯料组织的影响,并从形核与生长以及自孕育剂熔化状况对组织影响的角度探讨其细化机理。结果表明:随着熔体处理温度的升高,ZA94镁合金的晶粒尺寸呈先减小后增大的变化趋势;当熔体处理温度约为685℃时,晶粒尺寸最小,约为40μm。合理的熔体处理温度使孕育剂熔化率接近1,自孕育剂熔化后的残片和大尺寸的晶坯作为非均质形核的衬底,同时能量起伏和结构起伏促使其发生均质形核。
In order to explore the refining effect of melt temperature on the microstructure of ZA94 magnesium alloy semi-solid billets, the corresponding temperature gradient was designed according to the results of DSC analysis, and the effect of different melt treatment temperatures on the microstructure of semi-solid ZA94 magnesium alloy billets , And its mechanism of refinement was explored from the point of view of nucleation and growth, as well as the effect of melting from the inoculant on the tissue. The results show that with the increase of melt temperature, the grain size of ZA94 magnesium alloy decreases first and then increases. When the melt treatment temperature is about 685 ℃, the grain size is the smallest, about 40μm . Reasonable melt processing temperature so that the melting rate of inoculant close to 1, from inoculant melted debris and large-scale crystal blank as a heterogeneous nucleation substrate, while the energy fluctuations and structural ups and downs prompted the homogeneous nucleation .