Processing and characterization of laser cladded Cu-Sn-Zn coatings on cast aluminum alloys Available to Purchase

This paper describes the preliminary results of laser cladding experimentation of a Sn-bronze bearing alloy (88Cu, 10Sn, 2Zn, all wt %) onto cast aluminum alloys AA390 and AA333 for improving the surface properties. Experiments were performed while varying the key laser processing parameters which are laser power, traverse speed, and powder flowrate. Select preliminary results of the microstructural, microchemistry, microhardness, geometry, and crystallographic analyses using optical (OM) and scanning electron microscopy (SEM), x-ray energy dispersive spectroscopy (EDS) and x-ray diffractometry (XRD) are presented. The coatings were found to have very fine microstructures from rapid solidification (secondary dendrite arm spacings of 0.6 to 1.9 μm) with microhardnesses ranging from about 150 to 290 kg_f/mm². The interface has been found to have primary and lamellar eutectic CuAl₂ intermetallics, and Sn-rich secondary phases, in amounts depending on the extent of dilution. General observations of the coating characteristics (such as porosity, debonding, and dilution) and their dependence on processing parameters are also discussed.