Microstructure and mechanical properties of double continuously extruded Mg-Zn-Gd-based magnesium alloys
Microstructure and mechanical properties of double continuously extruded Mg-Zn-Gd-based magnesium alloys
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DOI：
10.1016/j.msea.2012.09.063
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发表时间：
2013-01-10
期刊：
影响因子：
6.4
通讯作者：
Ding, Wenjiang
中科院分区：
文献类型：
--
作者：
Huang, Hua;Yuan, Guangyin;Ding, Wenjiang
本文提出了一种新的热机械挤压工艺--双连续挤压工艺，即试样在一次挤压过程中连续挤压两次。研究了Mg98Zn1.92Gd0.08（at%，合金1）和Mg96.83Zn2.7Gd0.47（at%，合金2）在373 K下常规挤压和动态挤压后的显微组织和力学性能。结果表明，合金1中的第二相主要为Mg 2 Zn 3，合金2中的第二相主要为二十面体准晶相（I相）。在DCE之后，组织被细化，并且两种合金的平均晶粒尺寸小于1 μ m，这进一步改善了机械性能。这两种合金都表现出优异的机械性能，并且对于合金1，极限拉伸强度、屈服强度和断裂伸长率分别为434 MPa、410 MPa和14.6%;对于合金2，极限拉伸强度、屈服强度和断裂伸长率分别为444 MPa、417 MPa和13.1%。结果表明，直流电强化是一种有效的镁基合金晶粒细化和第二相弥散强化方法。(C)2012爱思唯尔有限公司版权所有。
Double continuous extrusion (DCE) is proposed here as a novel thermomechanical process which means that the sample is continuously extruded twice by one process. The microstructures and mechanical properties of Mg98Zn1.92Gd0.08 (at%, Alloy 1) and Mg96.83Zn2.7Gd0.47 (at%, Alloy 2) after conventional extrusion and DCE at 373 K were investigated. The results show that the major secondary phase in Alloy 1 is Mg2Zn3 and that in Alloy 2 is icosahedral quasicrystals phase (I-phase). After DCE, the microstructure is refined, and the average grain sizes of the both alloys are smaller than 1 mu m, and this further improves the mechanical properties. Both the alloys exhibit excellent mechanical properties, and the ultimate tensile strength, yield strength and elongation to failure are 434 MPa, 410 MPa and 14.6%, respectively, for Alloy 1; and 444 MPa, 417 MPa and 13.1%, respectively, for Alloy 2. The possible strengthening mechanisms were discussed and it was found that DCE is an effective method for Mg-based alloys strengthening by grain refinement and secondary phase dispersion. (C) 2012 Elsevier B.V. All rights reserved.