Effect of cold rolling and annealing temperature to the characteristics of α + β' phases in Cu-29.5Zn-2.5Al alloy produced by gravity casting

Abstract

Al-brass alloys (Cu29.5Zn2.5Al wt. %) were produced by gravity casting and homogenized at 800 °C for 2 h, resulting in a binary phase morphology identified as cubic α and martensitic βʹ phases through X-ray diffraction (XRD). Samples were then subsequently cold rolled and annealed at 150, 300, 400, and 600 °C for 30 minutes. Visible traces of slip, intersecting slip bands, and shear bands were observed in microstructure images of the samples after each progressive deformation stage. Deformation-induced martensites were present after 20 % cold rolling. Higher thickness reduction resulted in simultaneous strain hardening of the phases. Low temperature annealing slightly increased microhardness, of both α and βʹ, due to the formation of precipitates. SEM-EDX analysis showed that no solute segregation was found in annealed samples. Annealing at higher temperature resulted in conventional softening. Recrystallized equiaxed βʹ phase grains were visible after annealing at 600 °C.