铸态(TiB+TiC)/Ti复合材料组织和性能的研究
MICROSTRUCTURE AND PROPERTIES OF AS-CAST (TiB+TiC)/Ti COMPOSITES
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摘要: 利用钛与碳化硼及石墨之间的自蔓燃高温合成反应,经非自耗电弧熔炼工艺制备了TiB晶须和TiC粒子混杂增强的钛基复合材料。借助扫描电镜和透射电镜观察了复合材料的微观结构,结果表明:原位合成增强体均匀地分布在基体合金中,TiB增强体以晶须状生长,而TiC增强体以树枝状、等轴状生长。原位合成增强体与基体合金的界面非常干净,不存在界面反应产物,但TiC粒子周围的基体合金中存在高密度的位错。原位合成增强体的加入提高了复合材料的力学性能,合金化元素铝的加入不仅固溶强化了钛基体合金,同时使增强体长得更为细小,也有利于改善复合材料的性能。Abstract: TiB and TiC reinforced titanium matrix composites have been produced by non-consumable arc-melting technology utilizing the self-propagation high-temperature synthesis reactions between titanium and B4C, graphite. Microstructures have been observed by scanning electron microscopy and transmission electron microscopy. The results show that in situ synthesized reinforcements are distributed uniformly in matrix alloy. TiB grows in short-fibre shape and TiC grows in dendritic, equiaxed shapes. The interfaces between reinforcements and titanium matrix alloy are very clean. There is no any interfacial reaction. However, there are high-density dislocations near TiC particle. Mechanical properties have been improved due to the incorporation of reinforcements. The addition of aluminum element not only strengthens the titanium matrix alloy by solid solution strengthening, but also improves the mechanical properties of composites by refining the reinforcements.