反应烧结TiB_2－SiC复相陶瓷的物相反应、力学性能及残余应力

REACTION MECHANISMS, MECHANICAL PROPERTIES AND RESIDUAL STRESSES OF TiB_2-SiC COMPOSITES PRODUCED BY REACTIVE HOT PRESSING

利用ＴｉＨ２，Ｓｉ和Ｂ４Ｃ之间的化学反应制备ＴｉＢ２－ＳｉＣ复相陶瓷，研究了反应时物相生成机理及添加Ｎｉ对材料力学性能的影响．采用ＳＥＭ观察复相陶瓷的显微结构及裂纹扩展过程，用ＸＲＤ法测定了复相陶瓷内的残余应力，探讨了复相陶瓷的增韧机理同时，残余应力测试结果表明，精磨会给材料表面带来一定的机械加工应力，但随方向而异。

A new process of chemical reaction Si+2TiH2+B4C→ 2TiB2+SiC+2H2↑ for preparing TiB2-SiC composites has been proposed. The TiB2-SiC composites were fabricated by reactive hot pressing at 2000℃ under the pressure of 30MPa for 60min in Ar atmosphere. The effects of the addition amounts of Ni on the mechanical properties, the residual stresses and the toughening mechanisms of the composites were discussed.