Enhanced strength by precipitate modification in wrought Mg-Al-Ca alloy with trace Mn addition
Enhanced strength by precipitate modification in wrought Mg-Al-Ca alloy with trace Mn addition
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添加微量Mn的变形Mg-Al-Ca合金中通过沉淀变质提高强度
DOI：
10.1016/j.jallcom.2020.154689
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发表时间：
2020-09-25
影响因子：
6.2
通讯作者：
Zheng, M. Y.
中科院分区：
文献类型：
--
作者：
Li, Z. T.;Qiao, X. G.;Zheng, M. Y.
系统研究了微量锰（Mn）含量（0.1 wt%和0.3 wt%）对Mg-5.5Al-3Ca wt%合金力学性能和显微组织的影响。添加0.3 wt% Mn后，挤压态合金的屈服强度由366 MPa显著提高到402 MPa。铸态合金呈现由a-Mg相和（Mg, Al）(2)Ca相组成的枝晶结构。Mn的加入导致Al8Mn5相的形成，但对铸态合金的组织没有细化作用。挤压态Mg-5.5Al-3Ca-xMn合金呈现由动态再结晶（DRXed）细晶粒和粗晶粒组成的双峰组织。与无Mn合金相比，添加0.1Mn和0.3Mn时，在DRXed区析出的Mg2Ca纳米级颗粒直径更小，数密度更高。这些Mg2Ca颗粒具有更有效的分散强化和晶粒生长抑制作用，这被认为是Mn添加后屈服强度增加的主要原因。基于热力学计算和实验结果，讨论了Mg2Ca析出物的热稳定性和形成机理。(C) 2020 Elsevier B.V.版权所有
Effects of trace manganese (Mn) contents (0.1 wt% and 0.3 wt%) on mechanical properties and microstructure of the Mg-5.5Al-3Ca wt.% alloy were systematically investigated. By addition of 0.3 wt% Mn, the yield strength of the as-extruded alloy is significantly increased from 366 MPa to 402 MPa. The ascast alloys show a dendritic structure consists of a-Mg and (Mg, Al)(2)Ca phases. Mn addition leads to the formation of Al8Mn5 phase, but has no refining effect on the microstructure of the as-cast alloys. The as-extruded Mg-5.5Al-3Ca-xMn alloys exhibit a bimodal grain structure composed of dynamic recrystallized (DRXed) fine grains and coarse unDRXed grains. Compared with Mn free alloy, nano-scale Mg2Ca particles with a smaller diameter and higher number density are precipitated in the DRXed regions with 0.1Mn and 0.3Mn addition. These Mg2Ca particles are more effective in dispersion strengthening and grain growth inhibiting, which is considered to be the main reason for the increment on yield strength by Mn addition. Based on the thermaldynamic calculation and experimental results, the thermal stability and formation mechanism of the Mg2Ca precipitates were discussed. (C) 2020 Elsevier B.V. All rights reserved.