Effect of Cerium and Aluminium on the phase stability and properties of polycrystalline Cu-Al-Be shape memory alloys

Abstract

This study presents the outcomes of an investigation of the effect of wt% of cerium and Aluminium on the phases, crystal structure, microstructure, morphology, phase transformation temperatures, shape recovery ratio and mechanical properties of the polycrystalline Cu-Al-Be shape memory alloys (SMAs). SMAs exhibit martensite phase at room temperature up to 0.49 wt% of Be and ≥ 0.52 wt% of Be transforms to austenite phase. An increase in cerium by 0, 0.05, 0.1, 0.15 and 0.2 wt% decreases the grain size by 0, 70.87%, 82.73%, 83.8% and 94.6%, respectively. An increase in cerium increases the transformation temperatures owing to the Al-rich secondary precipitates, and the shape recovery ratio reduces. Alloying cerium of 0.1 wt% exhibits a maximum tensile strength of 474 ± 23 MPa with the ductility of 24.11 ± 1.42%. • Alloying cerium of 0.2 wt.% refines the grains to 25 μm from 463.45 μm. • Addition of beryllium >0.49 wt.% transforms martensite to metastable austenite. • Increase in Ce increases the transformation temperatures and deterioration in recovery.