Study of stress aging treatment and its effect on material properties of Cu-Zn alloys

Abstract

Stress aging treatment was conducted at various treatment conditions for three Cu-Zn alloys ; cold rolled 65:35 brass (BsS2A-H), annealed free cutting brass (MBsBD2A) and annealed 70:30 brass (BsBD1). The effect of treatment stress, temperature and time that control the stress aging reactions was studied and the change in mechanical properties and electrical conductivity after treatment studied. Strain aging (for cold rolled material) and plain aging (for annealed materials) were also conducted to compare the results with those of stress aging treatment. It was found that stress aging treatment has increased the proportional limit remarkably for the alloys treated. In case of free cutting brass (MBsBD2A), 0.2\% offset yield stress was increased markedly. Micromechanisms that govern the stress aging reactions were also discussed for each alloy. Optical and electron microscopic studies were attempted for the cold rolled 65:35 brass (BsS2A-H).