MICROSTRUCTURE AND PROPERTIES OF AS-CAST (TiB+TiC)/Ti COMPOSITES

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.