Investigation of microstructure and mechanical properties of hot worked NiAl bronze alloy with different deformation degree

Abstract

In this study, the forged NiAl bronze (NAB) were hot rolled with the deformation degree of 40%, 60%, 80%, 90% and 95% at 850°C, respectively. Effects of rolling deformation degree on the microstructure and mechanical properties of the NAB alloy were investigated. Scanning electron microscope (SEM), electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) methods were used to characterize the microstructure. The results show that α grains are refined by the dynamic recovery and recrystallization, penetration of β phase into α phase and particle-stimulated nucleation (PSN) of recrystallization during rolling. The refined grains make a main contribution to the increase of mechanical properties of rolled NAB. When the deformation degree is increased to 80%, the optimum tensile properties with ultimate strength of 861.3±8.5MPa, yield strength of 634.5±7MPa and elongation of 19.3±0.05% is obtained. With further increasing the deformation degree, the strength of rolled NAB alloy increase and the elongation decrease due to the increase of work hardening effect and the formation of martensitic nano-twins.