TiC-SKD11 함침 복합재의 온도에 따른 인장 특성과 파괴거동 변화

A composite having 60 vol% of TiC particles was successfully fabricated by the infiltration of molten SKD11 tool steel into a TiC preform. The density of this composite was achieved to be 25% lighter than conventional steels. The penetration of the liquid metal reached geometrically complex regions without any interfacial flaws. The interface between the TiC and steel was semi-coherent nature and had a specific orientation relationship, i.e., [111](alpha-Fe)//[001]//(Tic) , (112)(alpha-Fe)//(220)(Tic). Tensile tests were conducted at 25, 700, 750 and 800 degrees C. The composite exhibited the enhanced strength compared with the unreinforced SKD11, and its reinforcement was most effective at 800 degrees C. The TiC particles were fractured preferentially along the {100} cleavage plane, which was responsible for the main fracture of the composite. However, at and above 750 degrees C debonding of the TiC interface began to occur. The tensile fracture and strengthening mechanisms are discussed in terms of the TiC/matrix interface and dislocations.