原位自生(TiBw+TiCp)增强Ti60基复合材料的组织与力学性能

Microstructure and mechanical properties of reinforced Ti60 matrix composites by in-situ synthesized(TiBw+TiCp)

为获得更加耐热的钛基复合材料,采用真空热压烧结与原位自生技术,制备出不同体积分数的TiBw+TiCp混杂增强Ti60基复合材料,研究其显微组织、室温拉伸性能及强化机理。结果表明:原位自生的(TiBw+TiCp)增强相集聚在基体颗粒周围构成网状组织,与基体合金相比,网状分布的混杂增强相显著细化了基体的初始晶粒和集束尺寸,增强相体积分数为3.4%的(TiBw+TiCp)/Ti60复合材料室温屈服强度和抗拉强度较纯Ti60合金分别增大了18.1%和12.2%,其强度改善缘于TiBw与TiCp的载荷传递强化、C的固溶强化及细晶强化的共同作用。增强相体积分数相同的条件下,混杂增强网状结构复合材料的强度要优于单一强化的复合材料。

This paper intends to achieve more heat-resistant titanium matrix composites.By using vacuum hot-pressing sintering and in-situ synthesized technique,the study fabricates the hybrid reinforced Ti60 matrix composites with different volume fractions of TiB whiskers and TiC particles,and investigates the microstructure,room-temperature tensile properties and strengthening mechanism.The results show that in-situ synthesized hybrid(TiBw+TiCp)reinforcements are distributed around Ti60 matrix particles with a network microstructure.Comparied with Ti60 matrix alloy,the sizes of prior grain and colony are remarkably refined by the hybrid(TiBw+TiCp)reinforcements.The yield strength and ultimate tensile strength at room temperature of volume fraction of reinforcements 3.4%(TiBw+TiCp)/Ti60 composites increase by 18.1%and 12.2%compared with those of Ti60 matrix alloy,respectively.The strength is improved due to the combined actions of load transfer reinforcement,carbon solid solution strengthening,grain refinement strengthening of TiBw and TiCp.Under the condition of the same volume fraction of reinforcements,the network structured composites with hybrid reinforcements own superior strength over the single reinforced composites.