自孕育工藝參數(shù)對ZA96鎂合金半固態(tài)組織的影響及其交互本質(zhì)Effects of self-inoculation technological parameters on semi-solid microstructure of ZA96 magnesium alloy and interactive nature

采用自孕育法制備ZA96鎂合金半固態(tài)組織，研究自孕育工藝參數(shù)對ZA96鎂合金半固態(tài)組織的影響，并從溫度場的角度分析工藝參數(shù)之間相互作用的本質(zhì)。結(jié)果表明：采用自孕育法鑄造，能夠獲得合格的半固態(tài)坯料和漿料。工藝參數(shù)對半固態(tài)坯料組織影響較大，但對從導(dǎo)流器出口處收集到的漿料在半固態(tài)區(qū)間進(jìn)行保溫后，發(fā)現(xiàn)自孕育劑加入量對組織影響不大，而導(dǎo)流器角度的影響較大。熔體過熱度為80~95 ℃、自孕育劑加入量為5%、導(dǎo)流器角度為45°時，半固態(tài)坯料組織的晶粒平均尺寸較小，約為35.6 μm；或經(jīng)552 ℃、20 s保溫后，其晶粒尺寸為45 μm，圓整度為1.7。自孕育工藝參數(shù)交互作用的本質(zhì)在于通過自孕育參數(shù)的調(diào)整從而達(dá)到控制其形核的目的。推導(dǎo)出了熔體在導(dǎo)流器出口處的溫度與自孕育工藝參數(shù)之間的關(guān)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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