Effects of trace calcium and strontium on microstructure and properties of Cu-Cr alloys
Effects of trace calcium and strontium on microstructure and properties of Cu-Cr alloys
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DOI：
10.1016/j.jmst.2021.08.080
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发表时间：
2022-06-10
影响因子：
10.9
通讯作者：
Wei, Haigen
中科院分区：
文献类型：
--
作者：
Ma, Muzhi;Xiao, Zhu;Wei, Haigen
制备了Cu-0.57Cr-0.01Ca和Cu-0.58Cr-0.01Sr （wt.%）合金，并进行了热处理。并与Cu-0.57Cr （wt.%）合金的力学性能和显微组织进行了比较。结果表明，Ca和Sr元素的加入显著提高了Cu-Cr合金的抗软化性能。与Cu-Cr合金相比，Cu-Cr- ca和Cu-Cr- sr合金的变形组织在高温下更难再结晶，Cu-Cr- ca和Cu-Cr- sr合金中的Cr析出物尺寸更小，在任意时效状态下均呈FCC结构。Cu-Cr-Ca和Cu-Cr-Sr合金的高强度主要归因于高密度位错的位错强化和细Cr析出相的析出强化。第一性原理计算表明，在Cr析出物与铜基体界面处，Ca和Sr原子的分离在热力学上是有利的。这种偏析有效地阻碍了Cr析出相的生长，并显著增强了对位错和亚晶界运动的钉住作用，最终导致Cu-Cr合金的抗软化性能提高。(c) 2021年由Elsevier Ltd代表中国金属学会出版。
Cu-0.57Cr-0.01Ca and Cu-0.58Cr-0.01Sr (wt.%) alloys were fabricated and processed by thermo-mechanical treatment. Their mechanical and electrical properties and microstructure were investigated in detail and compared with those of a Cu-0.57Cr (wt.%) alloy. The results showed that the softening resistance of the Cu-Cr alloy was significantly improved by the additions of Ca and Sr elements. Compared with the Cu-Cr alloy, the deformation microstructure of the Cu-Cr-Ca and Cu-Cr-Sr alloys was more difficult to recrystallize at elevated temperatures, and the Cr precipitates in the Cu-Cr-Ca and Cu-Cr-Sr alloys were smaller in size and had an FCC structure at any given aging state. The high strengths of the Cu-Cr-Ca and Cu-Cr-Sr alloys were mainly attributed to the dislocation strengthening provided by high-density dislocations and the precipitate strengthening provided by fine Cr precipitates. First-principles calculation showed that the segregations of Ca and Sr atoms at interface between Cr precipitates and copper matrix were favorable in energetics. This segregation effectively hindered the growth of Cr precipitates and significantly enhanced the pinning effect on the motion of dislocations and subgrain boundaries, eventually leading to the improvement in the softening resistance of the Cu-Cr alloy. (c) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.