LASER CLADDING OF A COBALT-BASED ALLOY - PROCESSING PARAMETERS AND MICROSTRUCTURE

Laser cladding experiments with a hypoeutectic Stellite 6 alloy were c arried out with a low (1.67 mm/s), an intermediate (13.3 mm/s) and a v ery high (167 mm/s) scanning speed in order to examine the influence o f the processing conditions on the type, size and fraction of phases p resent. Altering the scanning speed over two orders of magnitude led t o a marked decrease in the microstructural size. With the fast process ing conditions, the fraction of interdendritic eutectic was also decre ased. The results are discussed based on a recent dendritic growth mod el for multicomponent alloys, using the solidification conditions dedu ced from a two-dimensional (2D) heat flux model and the phase diagram parameters determined with numerical calculations of the quaternary Co Cr-C-W phase diagram.