SOLID PARTICLE EROSION RESISTANCE OF DUCTILE WROUGHT SUPERALLOYS AND THEIR WELD OVERLAY COATINGS

The elevated temperature (400 degrees C) erosion behaviour of six weld overlay coatings and wrought alloys of similar compositions, was anal ysed and the relative ranking of their erosion resistance has been dev eloped. Microhardness tests performed on eroded samples showed that al l materials experienced significant plastic deformation. No relationsh ip was observed between hardness of the coatings at 400 degrees C and their erosion resistance. A new toughness parameter was developed base d on the measured area under the microhardness profile curve, which re presents the ability of a material to absorb impact energy. This param eter correlated well with erosion resistance for both weld overlays an d wrought alloys. Also, for the wrought alloys, an increase in area un der the true stress-strain curve or tensile toughness, corresponded to an increase in erosion resistance. The physical significance of the t oughness parameter is discussed along with relationships between hardn ess, tensile properties and erosion resistance. (C) 1998 Chapman & Hal l.