原位合成TiB/Ti复合材料的微观结构及力学性能

利用钛与硼之间的自蔓延高温合成反应经普通的熔铸工艺原位合成制备了TiB增强的钛基复合材料.通过XRD、SEM、TEM和HREM等分析方法测试了合成材料的物相及微观结构.结果表明原位合成的增强体为TiB,合金化元素铝的加入并不导致新相形成,增强体均匀地分布在基体合金上.由于TiB的B27结构导致TiB易于沿[010]方向生长而长成短纤维状.增强体与基体合金界面非常洁净,没有任何界面反应.由于原位合成增强体的加入,复合材料的力学性能与基体合金比较有了明显的提高.

Microstructure and Mechanical Properties of in situ Synthesized TiB/Ti Composites

TiB reinforced titanium matrix composites were fabricated by common casting technique utilizing the self propagating high temperature synthesis reaction between titanium and boron. X ray diffraction(XRD) was used to identify the phases of composites. The microstructures of composites were examined by means of scanning electron microscopy(SEM), transmission electron microscopy(TEM) and high resolution transmission electron microscopy(HREM). The results show that the composites consist of titanium and TiB phases. The addition of aluminum does not form new phase. The reinforcement is distributed uniformly in matrix alloy. TiB is liable to grow along the [010] direction due to its B27 structure. The interface between reinforcement and matrix alloy is very clean, there is no interfacial reaction. The mechanical properties of in situ synthesized titanium matrix composites are improved obviously compared with the matrix alloy due to the addition of TiB.