原位自生(TiC+TiB)/Ti复合材料的显微组织与残余应力

Microstructure and Residual Stress of In-situ Synthesized(TiC+TiB)/Ti Composites

通过钛、石墨、二硼化钛间的原位反应,并经真空熔炼、锻造、退火后制备得到了不同增强体(TiC,TiB)含量的(TiC+TiB)/Ti复合材料,研究了其物相组成与显微组织,并测试了其残余应力,通过建立残余应力数值拟合公式分析了微观残余应力之间的耦合关系。结果表明:钛基复合材料的基体组织为变形α组织,增强体分布均匀,其中TiC呈等轴状和不规则状,TiB呈短纤维状并沿锻造方向排列;TiC和TiB与钛基体因热膨胀系数不同而产生的微观残余应力分别为拉应力和压应力,当TiC与TiB体积比为1…1时微观残余应力的耦合系数为2.0。

（TiC＋TiB）/Ti composites with different reinforcement（TiC,TiB）content were prepared by insitu synthesis of Ti,graphite and TiB2 followed by vacuum melting,forging and annealing.The phase composition and microstructure were studied and the residual stresses were measured.Numerical simulation formulas of residual stresses were also established to analyze the coupling relationship between micro residual stresses.The results show that the Ti substrate in Ti matrix composites was composed of deformedα-microstructure and the reinforcements dispersed evenly.TiC had equiaxed or irregular shapes while TiB was short fibrous and distributed along forging direction.Mirco residual stresses generated by the mismatch of coefficients of thermal expansion between TiC or TiB and Ti substrate were tension and compression stresses,respectively.When the volume ratio of TiC to TiB was 1…1,the coupling coefficient of the micro residual stresses was 2.0.