Product Code: ICAL05_1403

Laser Clad WC Reinforced Ni-Based Intermetallic-Matrix Composites to Improve Cavitation Erosion Resistance
Authors:
Muthukannan Duraiselvam, Institut fr Schweiechnik und Trennende Fertigungsverfahren; Clausthal-Zellerfeld Niedersachen Germany
Rolf Galun, Institut fr Werkstoffkunde und Werkstofftechnik; Clausthal-Zellerfeld Niedersachen Germany
Volker Wesling, Institut fr Schweiechnik und Trennende Fertigungsverfahren; Clausthal-Zellerfeld Niedersachen Germany
Barry Mordike, Institu fr Werkstoffkunde und Werkstofftechnik; Clausthal-Zellerfeld Niedersachen Germany
Presented at ICALEO 2005

Cavitation erosion is a superficial damage encountered in fluid and steam handling systems which can be overcome by surface modification. Laser cladding is one of the important method that can modify the material surface with cavitation erosion resistive coating. Nickel based intermetallics have attractive properties such as low density, high melting point, high temperature strength, hot corrosion and cavitation erosion resistance. In the present work, Ni3Al-NiAl intermetallic matrix composites strengthened by WC reinforcement were produced on AISI 420 Martensitic stainless steel by direct powder injection laser cladding. 4 KW Nd:YAG laser with rotary-disk powder feeder was used in the experiment . Under optimized processing conditions, the clad layers were free of cracks and pores. The microstructure of the clad layer was characterized by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The microstructure of the coating was mainly composed of re-precipitated and refined WC particles and were dispersed uniformly throughout the Ni-Al matrix with few partially melted and un-melted WC particles. The X-ray diffraction analysis confirmed the presence of Ni3Al, NiAl and WC phases. The microhardness was measured using Vickers microhardness tester and was approximately 640 HV0.2. The cavitation erosion test was performed as per ASTM G 32-92 standards. The cavitation erosion resistance of the coating was improved substantially and was attributed to the ordered intermetallic structure and high work hardening ability of the matrix strengthened by WC reinforcement.