Deformation behavior of Mg-Zn-Gd-based alloys reinforced with quasicrystal and Laves phases at elevated temperatures
Deformation behavior of Mg-Zn-Gd-based alloys reinforced with quasicrystal and Laves phases at elevated temperatures
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DOI：
10.1016/j.jallcom.2006.03.027
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发表时间：
2007-01-16
影响因子：
6.2
通讯作者：
Lu, Cheng
中科院分区：
文献类型：
--
作者：
Liu, Yong;Yuan, Guangyin;Lu, Cheng
采用挤压工艺制备了准晶（I相）和Laves相增强的Mg-Zn-Gd和Mg-Zn-Gd-Cu合金。研究了这两种合金在室温和高温下的变形行为。由于I相的强化作用，Mg-Zn-Gd合金具有305 MPa的高抗拉强度和14.6%的延伸率，而含Laves相的Mg-Zn-Gd-Cu合金由于强化颗粒较多，屈服强度较高，达到217 MPa，但由于I相含量低，Laves相对称性差，易开裂，伸长率较低，仅为11.9（而I相具有非常高的对称性，因此本质上是各向同性的）。在高温下，Mg-Zn-Gd合金由于I相/基体界面能低，具有良好的塑性相容性，表现出较大的应变; Mg-Zn-Gd-Cu合金由于Laves相和准晶相的协同作用提供了更好的耐热性，具有比Mg-Zn-Gd合金更高的流变应力和应变指数，其可提供更有效的钉扎效应并抑制变形期间的晶粒生长。(c)2006 Elsevier B. V.保留所有权利。
Mg-Zn-Gd and Mg-Zn-Gd-Cu alloys, reinforced with quasicrystal (I-phase) and Laves phases, have been produced by extrusion process. The deformation behavior of these two alloys at room temperature and at elevated temperatures was investigated, respectively. The Mg-Zn-Gd alloy has high UTS of 305 MPa and elongation of 14.6% due to the strengthening effect of I-phase, while Mg-Zn-Gd-Cu alloy with Laves phases has higher yield stress of 217 MPa due to more strengthening particles and lower elongation of 11.9% resulting from the low content of I-phase and low symmetry of Laves phase due to which it cleaves easily (while the I-phase has a very high symmetry and therefore isotropic in nature). At high temperatures, Mg-Zn-Gd alloy shows large strain due to the excellent plastic compatibility coming from low interfacial energy of I-phase/matrix; Mg-Zn-Gd-Cu alloy has higher level of flow stress, strain exponent and more stable microstructure than Mg-Zn-Gd alloy due to better heat-resistance supplied by collaboration of Laves phases and quasicrystal phase, which can provide more effective pinning effect and suppress grain growth during deformation. (c) 2006 Elsevier B.V. All rights reserved.