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通过常规金属型铸造工艺制备准晶相增强的Mg-8Zn-4Al(ZA84)和Mg-8Zn-4Al-0.5Y(ZAY8405)合金,采用Gleeble-1500热模拟试验机在温度230℃和应变速率0.0015—1.5 s~(-1)的条件下,对准晶增强的Mg-Zn-Al(Y)合金的热压缩变形行为进行了研究.结果表明:ZA84和ZAY8405合金铸态组织主要由二十面体准晶和α-Mg所组成,Y的加入可进一步细化凝固过程中形成的准晶相;Mg-Zn-Al(Y)合金热变形过程中合金发生典型的动态再结晶,流变应力随应变速率增大而增大,并可通过幂指数模型进行描述,应变速率变化对ZAY8405合金流变应力的影响更大;热变形过程中,准晶可促进Mg-Zn-Al(Y)合金的动态再结晶,ZAY8405合金中弥散分布的细小准晶以及Y的加入更有利于孪生和动态再结晶的发生.
The quasicrystal reinforced Mg-8Zn-4Al (ZA84) and Mg-8Zn-4Al-0.5Y (ZAY8405) alloys were prepared by the conventional metal casting process. The specimens were heated at 230 ℃ and strain rate 0.0015 The results show that the as-cast microstructure of ZA84 and ZAY8405 alloy is mainly composed of icosahedron Quasicrystal and α-Mg. The addition of Y can further refine the quasicrystalline phase formed during the solidification process. The dynamic recrystallization of Mg-Zn-Al (Y) alloy occurs during hot deformation. The flow stress Strain rate increases and increases, and can be described by the power index model, ZAY8405 strain flow rate stress changes more influential; during the thermal deformation, quasicrystal can promote the Mg-Zn-Al (Y) alloy Dynamic recrystallization, ZAY8405 alloy dispersed in a small quasicrystal and Y is more conducive to the twin and dynamic recrystallization.