Investigation of hydroabrasive erosion of laser alloyed nickel and titanium based intermetallic matrix composites with TiC reinforcement

Abstract

B2–NiTi and Ti₃Al based single and dual phase intermetallic matrix composites (IMC) with TiC reinforcement were laser alloyed using Ni/Al–VC, Al–VC and Al–Cr₃C₂ powder mixtures. A sufficient amount of Ti from the substrate reacted with the injected alloy powder mixture to form Ti based intermetallics and TiC. The coatings were characterised by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and energy dispersive spectroscopy (EDS). The erosion resistance of the alloyed layers was characterised by high speed particle laden liquid impact erosion tests. The high work hardening ability of Ti₃Al IMC strengthened by TiC reinforcement improved the erosion resistance up to a factor of 1˙39. Compared to the single phase IMC, the dual phase IMC coatings were found not to be suitable for applications similar to the present test conditions due to possibly preferential removal of secondary precipitates. An attempt has been made to identify the influence of different depth sensing indentation (DSI) derived mechanical properties to the erosion resistance of the alloyed layers. The correlation indicates the combined contribution of hardness, strain hardening exponent, surface elasticity and yield strength on improving the erosion resistance.