Evolution of the microstructure, texture and thermal conductivity of as-extruded ZM60 magnesium alloy in pre-compression
Evolution of the microstructure, texture and thermal conductivity of as-extruded ZM60 magnesium alloy in pre-compression
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DOI：
10.1016/j.jallcom.2018.10.203
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发表时间：
2019-02
影响因子：
6.2
通讯作者：
L. Zhong;Yongjian Wang;Hong Luo;C. Luo;J. Peng
中科院分区：
文献类型：
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作者：
L. Zhong;Yongjian Wang;Hong Luo;C. Luo;J. Peng
系统研究了预压缩对挤压态ZM 60合金的组织演变、织构和热导率的影响。结果表明，沿挤压方向（ED）预压缩产生了透镜状{10-12}拉伸孪晶，形成了c轴//艾德织构组分，随着预压缩应变从0增加到8.3%，{10-12}拉伸孪晶的体积分数增加。这种微观结构的演变导致合金的晶体取向发生偏转，电子和声子在该方向上被缺陷散射的几率大大降低，电子和声子在该方向上的平均自由程得到改善，从而提高了合金的热导率。随着预压缩应变的进一步增加，观察到少量的{10-12}-{10-11}收缩孪晶和{10-12}-{10-11}-{10-12}三元孪晶，它们分别使晶粒的c轴重取向了约56°和约38°。由于c轴平行于艾德的晶粒体积分数减少，电子和声子的平均自由程减小，合金的热导率降低。因此，合金的热导率随预压缩应变的增加先增大后减小，预压缩应变为8.3%的合金热导率最高，为108.8 W/（m·K）。
A systematic study on the influence of pre-compression on the microstructure evolution, texture and thermal conductivity of as-extruded ZM60 alloy was performed. The results indicated that the lenticular shaped {10–12} extension twins were generated during the pre-compression along ED (extrusion direction), resulting in the formation of c-axis//ED texture component and the volume fraction of {10–12} extension twins increased as the pre-compression strains increased from zero to 8.3%. Such microstructure evolution led to a crystal orientation deflection of alloy, and the probability of electrons and phonons being scattered by defects in this direction became much lower, and the mean free path of electrons and phonons in this direction was improved, leading to an increase in the thermal conductivity of alloy. Upon further increase of pre-compression strain, a small amount of the {10–12}-{10–11} contraction twins and {10–12}-{10–11}-{10–12} ternary twins were observed, which introduced a reorientation of the c-axis of grains by ∼56° and ∼38°, respectively. So the mean free path of electrons and phonons decreased, due to the decrease of volume fraction of grains with c-axis parallel to ED, and the thermal conductivity of the alloy decreased. Therefore, the thermal conductivity of alloy first increased and then decreased with the increase of pre-compression strain, and the alloy with pre-compression strain of 8.3% showed the best thermal conductivity of 108.8 W/(m·K).