Effect of Varying Beryllium Addition on Microstructure, and Corrosion Behaviors of Cu-Zn-Al Shape Memory Alloys

Abstract

Due to their properties, potential for demonstrating shape memory behavior, and cheaper cost, copper-based SMA materials hold great promise for use in a variety of industrial and medical applications. This work used powder metallurgy to create Cu-based SMA using Cu-25Zn-4Al as the master alloy. The master alloy having Beryllium additions of (0.4, 0.8, and 1.2%wt.) was studied. After combining the powders, all samples were compacted using compaction stresses of (800 MPa). Then, the process of sintering in a tube furnace using argon gas has been accomplished in three stages, the first stage lasting two hours at 350°C, the second lasting two hours at 550°C, and the third lasting three hours at 900°C. All samples are treated with a solution heat treatment that involves heating them to 850 °C for an hour, quenching them quickly in saline ice water, and then aging them at 450 °C for 180 minutes. According to linear polarization tests the adding 1.2 weight percent of the Be to the base alloy (Cu-25Zn-4Al alloy) decreased corrosion rate by (95%) as compared to the base sample in a 3.5 weight percent NaCl solution. Keywords-Cu-Zn-Al shape memory alloys, corrosion behavior, shape memory properties, Beryllium, microstructure