准晶增强的Mg-Zn-Al-(Y)合金热压缩变形行为
准晶增强的Mg-Zn-Al-(Y)合金热压缩变形行为
复制标题
DOI：
10.3724/sp.j.1037.2011.00372
复制
发表时间：
2011-12
影响因子：
2.3
通讯作者：
童剑;黄华;袁广银;丁文江
中科院分区：
文献类型：
--
作者：
童剑;黄华;袁广银;丁文江
由于准晶相和镁基体之间的强界面，准晶相提供了强度和延展性的良好组合。在Gleeble-1500热模拟试验机上对准晶增强Mg-Zn-Al-（Y）基合金进行了恒变形温度为230 ℃、应变速率为0.0015 ~ 1.5 s-1的热压缩试验。研究了Mg-Zn-Al-（Y）合金热压缩变形过程中的微观组织演变以及流变应力与应变速率的关系。XRD和SAED结果表明，铸态Mg-8 Zn-4Al（ZA 84）和Mg-8 Zn-4Al-0. 5 Y（ZAY 8405）的显微组织均由二十面体准晶相和α-Mg基体组成。ZA 84和ZAY 8405合金中准晶的化学计量组成分别为Mg_（38）Zn_（43）Al_（19）和Mg_（51）Zn_（30）Al_（19）。热压缩过程中发生动态再结晶（DRX），在一定的压缩温度下，随着应变速率的增加，流变应力增加，可用幂指数方程表示。由于准晶相的细化和弥散，ZAY 8405合金更容易发生形变孪晶和动态再结晶。
Quasicrystal phase offers a good combination of strength and ductility due to the strong interface between the quasicrystal phase and the Mg-matrix. Hot compression tests of Mg-Zn-Al-(Y) based alloys reinforced with quasicrystal were performed on Gleeble-1500 thermal simulation machine at a constant deformation temperature of 230 and strain rates ranged from 0.0015 s �1 to 1.5 s �1 . Microstructure evolution of hot-compressed Mg-Zn-Al-(Y) alloys and the relationship between flow stress and strain rate were studied. XRD and SAED results show that the microstructures of as-cast Mg-8Zn-4Al (ZA84) and Mg-8Zn-4Al-0.5Y (ZAY8405) are composed of icosahedral quasicrystal phase and α-Mg matrix. The quasicrystals in ZA84 and ZAY8405 alloys have a stoichiometric composition of Mg38Zn43Al19 and Mg51Zn30Al19 respectively. Dynamic recrystalization (DRX) take place during hot compression and the flow stress increases when increasing the strain rate at a constant compression temperature, which can be represented by the Power Exponential Equation. Deformation twinning and dynamic recrystalization are easier to take place in ZAY8405 alloys due to the refined and dispersed quasicrystal phase with Y addition.