School of Materials Science and Engineering , Shandong University of Science and Technology , Qingdao 266590 , Shandong , P.R. China.
ACS Appl Mater Interfaces. 2018 May 16;10(19):16783-16792. doi: 10.1021/acsami.8b02023. Epub 2018 May 1.
In this work, TiAl(C, N) solid solution with lamellar structure-enhanced TiAl matrix composites was synthesized by vacuum arc melting, using bulk g-CN, Ti, and Al powders as raw materials. The phases, microstructures, interfaces, and mechanical properties were investigated. MAX phase of TiAl(C, N) solid solution with lamellar structure was formed. During the melting process, first, CN reacted with Ti to form Ti(C, N) by Ti + CN → Ti(C, N). Then TiAl(C, N) was formed by a peritectic reaction of TiAl(l) + Ti(C, N)(s) → TiAl(C, N). CN is the single reactant that provides C and N simultaneously to final product of TiAl(C, N). The interfaces of TiAl//TiAl(C, N) and TiAl(C, N)//Ti(C, N) display perfect orientation relationships with low misfit values. The microhardness, compressive strength, and strain of best-performing TiAl-10 mol % TiAl(C, N) composite were improved by 45%, 55.7%, and 50% compared with the TiAl alloy, respectively. Uniformly distributed TiAl(C, N) and unreacted Ti(C, N) particles contributed to the grain refinement and reinforcement of the TiAl matrix. Laminated tearing, particle pull-out, and the crack-arresting of TiAl(C, N) are crucial for the improvement in compressive strength and plasticity of the composites.
在这项工作中，采用真空电弧熔炼技术，以块状 g-CN、Ti 和 Al 粉末为原料，合成了具有层状结构增强 TiAl 基体复合材料的 TiAl(C，N)固溶体。研究了其相组成、微观结构、界面和力学性能。形成了具有层状结构的 MAX 相 TiAl(C，N)固溶体。在熔化过程中，首先，CN 与 Ti 反应形成 Ti(C，N)，反应式为 Ti + CN → Ti(C，N)。然后通过 TiAl(l) + Ti(C，N)(s) → TiAl(C，N)的包晶反应形成 TiAl(C，N)。CN 是唯一同时为 TiAl(C，N)最终产物提供 C 和 N 的反应物。TiAl//TiAl(C，N)和 TiAl(C，N)//Ti(C，N)界面显示出完美的取向关系，具有较低的失配值。与 TiAl 合金相比，性能最佳的 TiAl-10mol%TiAl(C，N)复合材料的显微硬度、抗压强度和应变分别提高了 45%、55.7%和 50%。均匀分布的 TiAl(C，N)和未反应的 Ti(C，N)颗粒有助于细化和增强 TiAl 基体。TiAl(C，N)的分层撕裂、颗粒拔出和裂纹止裂对复合材料抗压强度和塑性的提高至关重要。
