Spatial and microstructural dependence of mechanical properties and wear performance of functionally graded Al–TiAl3 in situ composite

Abstract

Effect of morphology and spatial distribution of TiAl3 particles on the hardness, the tensile behavior and the wear performance of functionally graded Al–TiAl3 in situ composite (FGC) was investigated. Initially, FGC was produced by interaction between solid Ti and liquid Al. Based on the spatial distribution and morphology of TiAl3 particles in the microstructure of FGC, three distinctive regions including blocky-particle region, mixed-particle region (blocky and short plate particles) and lengthy plate-particle region were studied. Results of this study showed that the blocky-particle region had promoted tensile strength as well as highly improved wear resistance. In addition, this region with higher density of blocky particles and low interparticle spacing showed a brittle fracture. The mixed-particle region with a lower density of blocky particles had a ductile fracture mechanism while the plate-particle region showed cleavage fracture. The dominant wear mechanism for regions including blocky particles was determined to be mild oxidation while it was delamination wear for regions containing plate particles. Finally, correlation between mechanical properties, wear resistance and microstructure of FGC was discussed.