Microstructural and Mechanical behaviour of Nickel Aluminum Bronze alloys

The present investigation reports on microstructure and mechanical characterization of permanent and shell moulded Nickel Aluminum Bronze alloy Castings (NAB) (AB2) melted in Medium Frequency coreless Induction furnace. The mechanical properties studied consisted of Tensile strength, Yield Strength, ductility on one hand, Optical microscopy and grain size measurements on the other. Effect of zirconium addition on the microstructure and mechanical characteristics of Permanent and shell moulded castings have been studied. The results of this investigation reveal that microstructures consisted of dispersed particles in the matrix of copper solid solution both in permanent and shell moulded castings. Shell moulded castings exhibited extensive grain refinement compared to Permanent moulded castings. Very high values of Tensile Strength, Yield strength and Elongation values are obtained for the Nickel Aluminum Bronze alloys. Shell moulded castings have exhibited superior mechanical properties than Permanent moulded castings in all the characteristic/property values obtained. (paper)