等通道转角挤压制备Ag/Ti3AlC2复合材料及其热处理研究

采用等通道转角挤压(Equal Channel Angular Pressing, ECAP)并结合热处理制备了Ag/Ti₃AlC₂复合材料。通过XRD、SEM分析物相和形貌, 探讨了不同热处理条件下Ag/Ti₃AlC₂材料的电阻率和力学性能。结果表明: 采用ECAP可以明显致密化Ag/Ti₃AlC₂疏松坯体, 且在ECAP的剪切作用下, 层片状Ti₃AlC₂颗粒沿基面分层并按一定方向排列。Ti₃AlC₂的定向排列使材料性能呈现各向异性: 垂直于Ti₃AlC₂排列方向时, Ag/Ti₃AlC₂材料的电阻率和压缩强度更高。后续热处理提升了Ag/Ti₃AlC₂的电阻率和压缩强度, 并发现在800 ℃时增幅显著。这主要归因于Ag与Ti₃AlC₂在高温下明显增强的界面反应。本研究表明采用ECAP方法可以在致密化Ag/MAX复合材料的同时调控其显微组织, 而结合热处理可以进一步调控界面反应并优化材料性能。

Ag/Ti3AlC2 Composites Prepared by Equal Channel Angular Pressing Followed by Heat Treatment

Equal channel angular pressing (ECAP) followed by heat treatment was carried out to prepare Ag/Ti₃AlC₂ composites. Effects of heat treatment on the electrical resistivities and mechanical properties of the Ag/Ti₃AlC₂ composites were investigated. Results show that ECAP effectively densifies the Ag/Ti₃AlC₂ compacts, and layered Ti₃AlC₂ particles are delaminated and aligned due to shearing effect during ECAP. Alignment of Ti₃AlC₂ particles resulted in anisotropy of electrical and mechanical properties of the composites. Perpendicular to the alignment of Ti₃AlC₂ particles displayed high resistivity and compressive strength. Moreover, resistivity and compressive strength increased with following heat treatment, yielding the maximum at 800 ℃. These increments are attributed to the enhanced interfacial reactions between Ag and Ti₃AlC₂ at high temperatures. Findings in this study indicate that densification and microstructural control of Ag/MAX composites can be achieved simultaneously by ECAP, while the following heat treatment can tailor their properties.