Particle-Laden Liquid Impact Erosion Characteristics of Laser Clad Ni-Based Intermetallic Matrix Composites with TiC and WC Reinforcements
Muthukannan Duraiselvam, Rolf Galun, Stephan Siegmann, Volker Wesling and Barry L. Mordike
NiAl-Ni 3 Al intermetallic composites (IC)and intermetallic matrix composites (IMC) with TiC and WC reinforcement were laser clad to increase the solid-liquid impact erosion resistance of AISI 420 Martensitic stainless steel.Laser process parameter optimisation and pre- and post-heat treatment of the laser clad specimens were carried out to minimise porosity and sensitivity to crack formation. The erosion resistance of nickel aluminide IC coating and IMC coating with WC reinforcement were improved by a factor of 1.4 and 1.7, respectively. The ordered intermetallic structure and high work hardening ability was attributed to better erosion resistance of the nickel aluminide IC coatings. The strength of IC coatings further improved by the WC particles, which precipitated along the grain boundaries of the nickel aluminide matrix; improving the erosion resistance. The poor performance of IMC coatings with TiC reinforcement was due to the presence of unmelted and partially melted TiC particles in the matrix which acted as initiation sites for erosive attack. This demonstrated that the microstructural features and the choice of reinforcement addition were important in improving the erosion resistance. The hardness and elastic modulus were correlated with the erosion resistance. It was concluded that the hardness alone could not improve the solid-liquid impact erosion resistance of the coatings.