TiC_p颗粒增强钛基复合材料的强化机理研究

Strengthening Mechanism in TiC-Particle-Reinforced Titanium Matrix Composite

利用 SEM,TEM对 Ti C粒子增强的钛基复合材料的强化方式进行研究 ,得出 :当反应界面厚度控制在 0 .5μm～ 2 μm时 ,界面将起到良好的传递载荷的作用 ,使粒子承载。当粒子的粒度较小 (d P<1μm) ,Orowan强化机制将参与材料强化 ,而当粒子较大时 (d P>1μm) ,阻碍位错滑移。由于两相之间的不均匀变形 ,在界面形成较高的应力集中 ,阻碍形变 ,并可产生形变位错源 ,使基体中位错增殖 ,形成位错胞 ,强化基体。当扩展裂纹遇到 Ti C粒子 ,使扩展路径发生偏转 ,增加裂纹扩展能量 ,提高了材料的强度。

The strengthening mechanisms in TiC particle reinforced titanium matrix composite has been studied. The experimental results indicate that as the interfacial width is in the range 0 5μm to 2μm,the interface will play good role of dilivering force. If the particle diameter ( d p ) is less than 1μm, the TiC particles will strengthen the material (Orowan mechanism); but big particles ( d p >1μm) will prevent dislocation slipping. The deformative difference between the TiC particles and the matrix produces stress concentration, which obstructs deformation, produces dislocation sources, increases the dislocation density in matrix, and produces a dislocation cell structure which strengthens the matrix. As propagated cracks meet TiC particles, the cracks will change their orientation. The propagation energy increases, resulting in a strengthening of the composites.