The effect of heat input on the microstructure and properties of nickel aluminum bronze laser clad with a consumable of composition Cu-9.0Al-4.6Ni-3.9Fe-1.2Mn

Abstract

The effect of heat input in the laser cladding of nickel aluminum bronze was investigated. Nickel aluminum bronze castings were clad with a consumable of the composition Cu-9.0Al-4.6Ni-3.9Fe-1.2Mn and exposed to a variety of heat inputs from 42.5 to 595 J/mm. At the lowest heat input, the deposit microstructure was almost entirely martensitic. Increases in heat input caused the amount of α to increase. Depending upon heat input, the α was present as grain boundary allotriomorphs, secondary Widmanstatten α sideplates, and intragranular Widmanstatten α precipitates. The reheated zones were of lower hardness and, at all heat inputs, consisted of a mixture of grain boundary allotriomorphs and Widmanstatten α and martensite. Laser cladding improved the corrosion- and cavitation-erosion resistance of the surfaces but reduced their ductility. The properties of the clad surfaces depended on heat input.