Competitive precipitation behavior of hybrid reinforcements in copper matrix composites fabricated by powder metallurgy
Competitive precipitation behavior of hybrid reinforcements in copper matrix composites fabricated by powder metallurgy
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DOI：
10.1007/s12613-020-2052-x
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发表时间：
2021-06
期刊：
影响因子：
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通讯作者：
Tao Lan;Yihui Jiang;Xiaojun Zhang;F. Cao;S. Liang
中科院分区：
文献类型：
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作者：
Tao Lan;Yihui Jiang;Xiaojun Zhang;F. Cao;S. Liang
采用粉末冶金方法制备了原位杂化硼化钛晶须（TiBw）和二硼化钛颗粒（TiB2p）增强的铜基复合材料。微观结构观察显示 TiBwan 和 TiB2p 之间存在竞争沉淀行为，其中两种增强材料的相对含量随烧结温度的变化而变化。基于热力学和动力学评估，讨论了混合增强体的析出机制，热力学有利于局部熔融区形成 TiBwan 和 TiB2p。沉淀动力学主要由B原子的固态扩散控制。通过形成致密的化合物层，原位反应分为两个阶段，分别以Zener生长和Dybkov生长为主。因此，竞争性沉淀行为归因于反应过程中生长模型的转变。
Copper matrix composites reinforced byin situ-formed hybrid titanium boride whiskers (TiBw) and titanium diboride particles (TiB2p) were fabricated by powder metallurgy. Microstructural observations showed competitive precipitation behavior between TiBwand TiB2p, where the relative contents of the two reinforcements varied with sintering temperature. Based on thermodynamic and kinetic assessments, the precipitation mechanisms of the hybrid reinforcements were discussed, and the formation of both TiBwand TiB2pfrom the local melting zone was thermodynamically favored. The precipitation kinetics were mainly controlled by a solid-state diffusion of B atoms. By forming a compact compound layer,in situreactions were divided into two stages, where Zener growth and Dybkov growth prevailed, respectively. Accordingly, the competitive precipitation behavior was attributed to the transition of the growth model during the reaction process.