Effects of extrusion and Ag, Zn addition on the age-hardening response and microstructure of a Mg-7Sn alloy
Effects of extrusion and Ag, Zn addition on the age-hardening response and microstructure of a Mg-7Sn alloy
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挤压和Ag、Zn添加对Mg-7Sn合金时效硬化反应和显微组织的影响
DOI：
10.1016/j.msea.2016.03.037
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发表时间：
2016-04-20
期刊：
影响因子：
6.4
通讯作者：
Huang, Weigang
中科院分区：
文献类型：
--
作者：
Huang, Xuefei;Wu, Aolu;Huang, Weigang
研究了Ag和Zn的挤压和宏观合金化对Mg-7Sn合金时效硬化行为和显微组织的影响。结果表明：挤压工艺和挤压复合添加2 wt%Ag或2 wt%Ag+1 wt%Zn均能显著提高未挤压Mg-7Sn合金的硬度，未时效态硬度分别从46 HV提高到52 HV、72.5 HV和77.5 HV；强化效果主要是由于挤压过程中动态析出和晶粒细化所致。由于动态析出导致合金元素耗损，在160℃人工时效下，Mg-7Sn挤压合金的基体和宏观合金的硬度增量几乎相等（约10 HV）。挤压合金的晶粒尺寸呈双峰型分布，主要是动态再结晶的细晶粒和少量严重变形的粗晶粒。Mg2Sn析出物有两种类型。一种是随机分布的球形颗粒，另一种是在基体内部形成的板条。在挤压Mg-7Sn合金中加入Ag或Ag+Zn可以显著细化Mg2Sn板条的尺寸。挤压后的Mg-7Sn-2Ag-1Zn合金沿晶界形成块状的epsilon′-Mg54Ag12相。(C) 2016 Elsevier B.V.版权所有
The effects of extrusion and macro-alloying of Ag and Zn on the age-hardening behavior and microstructure of a Mg-7Sn alloy were investigated. The results show that the extrusion process and extrusion combined with 2 wt%Ag or 2 wt%Ag+1 wt%Zn addition can significantly improve the hardness of the unextruded Mg-7Sn alloy from 46 HV to 52 HV, 72.5 HV and 77.5 HV, respectively at the unaged state. The strengthening effect is mainly attributed to the dynamic precipitation and much refined grain size obtained by the extrusion process. Due to the depletion of the alloying elements by dynamic precipitation, the hardness increments resulted from artificial ageing at 160 degrees C are almost equal (around 10 HV) for the base and macro-alloyed Mg-7Sn extruded alloys. The extruded alloys exhibit a bimodal grain size distribution containing major dynamically recrystallized fine grains and minor severely deformed coarse grains. There are two types of Mg2Sn precipitates. One is the spherical particles distributed randomly and the other is the laths formed within the matrix. Ag or Ag+Zn addition to the extruded Mg-7Sn alloy can significantly refine the size of Mg2Sn laths. Blocky epsilon'-Mg54Ag12 phase is also formed along grain boundaries in the extruded Mg-7Sn-2Ag-1Zn alloy. (C) 2016 Elsevier B.V. All rights reserved.