Microstructure, mechanical and corrosion properties of the 50%Ni-47%Ti-3%Cu shape memory alloy

Abstract

in this study, the mechanical, microstructure and corrosion properties of Nickel-Titanium-Copper shape recovery alloys were investigated. The alloy was prepared by the powder metallurgy method, where powders of 50% Titanium, 47 % Nickel and 3% Cupper were mixed and cold compacted at (600,700 and 800) MPa to form cylindrical samples of (11mm diameter × 16.5mm length) and (11mm diameter ×5 mm length). After compaction process the specimens had more green strength for handling. The samples were subsequently sintered at a temperature of (850,900 and 950) °C for a period of 5 hours in an electric vacuum tube furnace. Multiple tests were conducted on the alloys including porosity measurements, scanning electron microscopy (SEM), compression strength, shape memory effect and corrosion rate test. The results indicate improvement in compression strength and shape memory effect with low sintering temperature and high compacting pressure as well as reduction in the corrosion rate.