Influence of Heat Treatment on Microstructure and Hardness of Nickel Aluminium Bronze (Cu-10al-5ni-5fe)

Abstract

In this investigation two types of heat treatments, solutionizing and ageing were employed to nickel-aluminium bronze (NAB alloy) containing 10% Al, 5% Fe and 5% Ni as the alloying elements. Heat treatment was done to access their influence on the microstructural and hardness. Solutionizing temperature carried out at 850 o C and 900 o C for duration of 30 min, 60 min, 90 min and 120 min. similarly, ageing was carried out at 300 o C and 500 o C for the duration of 120 min and 180 min. The heat treated samples were subjected to water quenching in order to bring them to ambient temperature. Microstructural studies was also carried out of as cast alloy as well as after Solutionizing and Ageing.Hardness of the samples was measured in as cast and heat treated (solutionized and aged at different temperatures and durations) conditions. The hardness of the alloy increased after the solutionizing and ageing treatments compared to the as cast one. Also, the samples aged at 400 o C for 3 hrs attained the highest hardness. Optimization was done based on the best combination of hardness and microstructural homogeneity attained by the samples during the heat treatment.