自孕育工艺参数对ZA96镁合金半固态组织的影响及其交互本质Effects of self-inoculation technological parameters on semi-solid microstructure of ZA96 magnesium alloy and interactive nature

采用自孕育法制备ZA96镁合金半固态组织，研究自孕育工艺参数对ZA96镁合金半固态组织的影响，并从温度场的角度分析工艺参数之间相互作用的本质。结果表明：采用自孕育法铸造，能够获得合格的半固态坯料和浆料。工艺参数对半固态坯料组织影响较大，但对从导流器出口处收集到的浆料在半固态区间进行保温后，发现自孕育剂加入量对组织影响不大，而导流器角度的影响较大。熔体过热度为80~95 ℃、自孕育剂加入量为5%、导流器角度为45°时，半固态坯料组织的晶粒平均尺寸较小，约为35.6 μm；或经552 ℃、20 s保温后，其晶粒尺寸为45 μm，圆整度为1.7。自孕育工艺参数交互作用的本质在于通过自孕育参数的调整从而达到控制其形核的目的。推导出了熔体在导流器出口处的温度与自孕育工艺参数之间的关系式。

Semi-solid microstructure of ZA96 magnesium alloy was prepared by self-inoculation method (SIM). The effects of self-inoculation technological parameters on the microstructure of semi-solid ZA96 magnesium alloy were investigated. And the nature of interactive effect between technological parameters was analyzed from the standpoint of temperature field. The results show that high-quality semi-solid billets and slurry can be obtained by SIM. The effects of self-inoculation technological parameters on the microstructure of semi-solid billets are bigger, but for the microstructure of semi-solid slurry which is collected from the exit of the fluid director and holding in semi-solid interval, the effect of self-inoculants is smaller, but that of the angle of fluid director is bigger. When the superheat of the melt is 80-95 ℃ and the addition of self-inoculants is 5% and the angle of fluid director is 45°, the grain size of semi-solid billet is 35.6 μm; or after holding 20 s at 552 ℃, the grain size of primary phase is 45μm and the roundness is 1.7. The interactive nature of self-inoculation technology parameters is to control nucleation by coordinating them. The formula between the temperature of melt in the exit of fluid director and self-inoculation technological parameters was derived.

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