原位合成层状Ti-(TiB＋TiC)/Ti复合材料的组织与力学性能

Microstructure and Mechanical Properties of In-situ Fabricated Laminated Ti-(TiB+TiC)/Ti Composites

鉴于颗粒增强钛基复合材料在提高强度的同时会引起塑韧性的下降,借鉴性能优异生物材料的叠层微观结构,利用粉末冶金结合热加工工艺(热锻+退火)的方法,制备了增强体体积分数为5%~15%的原位合成层状Ti-(TiB+TiC)/Ti复合材料,并对其组织和力学性能进行了研究。结果表明:复合材料组织完全致密化,复合层中团聚的增强体被分散,纯钛层α晶粒沿锻造方向排列;复合材料的室温抗拉强度较纯钛的提高近一倍,退火后其伸长率明显提升;随增强体体积分数的增加,复合材料的强度稍有提高,但塑性下降较为明显,增强体体积分数为5%的复合材料具备优异的综合力学性能,与增强体体积分数为15%的复合材料相比,强度仅降低了4%,但伸长率却增加了3.8倍。

The particulate reinforced titanium matrix composites can improve the strength while reduce the ductility and toughness, therefore learned from the multilayer microstructure of nature biological materials with excellent properties, the laminated structure Ti-（TiB＋TiC）/Ti composites with 5%- 15% volume fraction of reinforcements were prepared by powder metallurgy and hot working processes （hot forging and annealing）. Microstructure and mechanical properties of Ti-（TiB＋TiC）/Ti composites were also analyzed. The results show that the microstructure of composites was densification, and the agglomerated reinforcements in the composite layer were well dispersed and distributed uniformly in the titanium matrix. Meanwhile, the α grains in pure titanium layer aligned along the forging direction. The room temperature tensile strength of laminated Ti-（TiB ＋ TiC）/Ti composites was nearly double than that of pure titanium and elongation had the significant improvement after annealing. When the volume fraction of reinforcements increased, the strength of composites improved but the ductility dereased apparently. The composites with 5% volume fraction of reinforcements performed the excellent mechanical properties, which obtained an improvement by 3.8 times in elongation with 4% reduction in strength compared with composites with 15% volume fraction of reinforcements.