Ti/TiC金属基复合材料的显微组织

Microstructure of Ti-TiC Metal-Matrix Composite

用金相、SEM和TEM观察和分析了Ti-15S/TiC颗粒增强复合材料的显微结构。复合体用PTMP工艺制备并经不同温度热处理。复合体中基体由等轴α相晶粒和少量β_转组成,晶粒尺寸约等于TiC粒子平均尺寸,但比同样条件下未复合基材小得多,在1050℃退火后复合体中β_转也比未复合材中少许多。复合体基体中位错密度远高于未复合材。复合体中TiC粒子有降解反应,在粒子周围形成反应环带,环带结晶结构同TiC一致。但晶胞略小。TiC粒子内有分层平行排列的位错,但没有观察到将粒子心部和反应层分开的高密度位错网络。

The optical microscopy, SEM and TEM are used for analyzing the microstructure of Ti- 15S-TiC composite which is made by PTMP procedure, and heat-treated at different temperatures. The matrix in the composites consists of equi axed a grains and a few of the transformation β phase (β_T). The average size of a grains in composites is approximate same as that of TiC particles, but much less than the grain size of unreinforced Ti-15S alloy. The composite matrix has a less β_T content and a higher dislocation density than the unreinforced Ti-15S at the same condition.The SED analyses of TiC particles show that there is a reaction zone surrounding TiC particles. The outer reaction annulus and interior of TiC particle have the same lattice structure, but the lattice parameter of the outer annulus is slightly smaller than in the interion. There is a layered paraller dislocation arrangment in TiC particles, but no dislocation network at the boundary between the outer annulus and interior is observed.