Feng Yangju, Li Bing, Cui Guorong, Zhang Wencong
School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209, China.
Materials (Basel). 2017 Oct 25;10(11):1227. doi: 10.3390/ma10111227.
In-situ TiB whisker-reinforced Ti-6Al-4V (TC4) titanium matrix composites (TiBw/TC4) with quasi-continuous networks were successfully fabricated by vacuum hot-pressing sintering. The effects of the hot-hydrostatic canned extrusion on stock utilization, microstructure and mechanical properties of the TiBw/TC4 composites were investigated. It was satisfactory that the utilization of composites could be obviously improved by canned extrusion compared to that extruded without canned extrusion. The microstructure results showed that after canned extrusion the grain was refined and the TiB whiskers were distributed from a random array state to a state in which the whiskers were distributed along the extrusion direction. The properties testing results revealed that the tensile strength, the hardness and the ductility of the composites all significantly improved after extrusion due to the grain refinement and orientation of the TiB whisker caused by extrusion. Tensile fracture results showed that when the TiB whiskers were randomly distributed only part of them played a role in strengthening the matrix during the deformation process (as-sintered composites), while when the TiB whiskers were oriented all whiskers could strengthen the matrix during the tensile testing process (as-extruded composites).
通过真空热压烧结成功制备了具有准连续网络结构的原位TiB晶须增强Ti-6Al-4V（TC4）钛基复合材料（TiBw/TC4）。研究了热等静压包套挤压对TiBw/TC4复合材料坯料利用率、微观结构和力学性能的影响。结果表明，与无包套挤压相比，包套挤压能显著提高复合材料的利用率。微观结构结果表明，包套挤压后晶粒细化，TiB晶须从随机排列状态转变为沿挤压方向分布的状态。性能测试结果表明，由于挤压导致晶粒细化和TiB晶须取向，复合材料的拉伸强度、硬度和延展性在挤压后均显著提高。拉伸断裂结果表明，当TiB晶须随机分布时，在变形过程中只有部分晶须对基体起到强化作用（烧结态复合材料），而当TiB晶须取向时，在拉伸测试过程中所有晶须都能强化基体（挤压态复合材料）。
