TiB＋TiC＋La2O3三元颗粒增强IMI834钛基复合材料的裂纹扩展行为

Crack Propagation Behavior of TiB+TiC+La_2O_3 Ternary Particulate Reinforced IMI834 Titanium Matrix Composite

利用原位合成法制备了TiB+TiC+La_2O_3三元颗粒增强IMI834钛基复合材料并进行锻造和去应力退火处理,研究了其显微组织、拉伸性能和裂纹扩展行为。结果表明:原位生成的TiB,TiC,La_2O_3增强颗粒均匀分布于钛合金基体中,增强体界面洁净,但部分TiB增强体发生破碎;复合材料的屈服强度和抗拉强度分别为1 010 MPa和1 150 MPa,比IMI834钛合金的分别提高了9%和8%;在缺陷分布较少区域,复合材料中的裂纹以沿晶扩展为主,扩展路径曲折,在缺陷分布较多区域,破碎增强体引入的缺陷改变了裂纹扩展方向。

TiB＋ TiC＋ La2O3 ternary particulate reinforced IMI834 titanium matrix composite was in-situ synthesized, and then forged and treated by stress relief annealing. The microstructure, tensile properties and the crack propagation behavior of the composite were investigated. The results show that the in-situ synthesized TiB, TiC and La2 03 reinforcements dispersed homogenously in the titanium alloy matrix, forming a clean interface, and some TiB reinforcements were broken. The yield and tensile strength of the composite were 1 010 MPa and 1 150 MPa, respectively, improved by 9%o and 8~~ compared with those of IMI834 titaniuim alloy. Intergranular crack propagation mainly occurred in the region containing fewer defects of the composite, and the crack propagation path was tortuous. In the region containing more defects, defects caused by broken reinforcements changed the crack propagation direction.