Enhanced superelasticity and notable elastocaloric effect of Cu71Al17.5Mn11.5 shape memory alloys by laser-based powder bed fusion

Abstract

Cu-based shape memory alloys (SMAs) with highly oriented columnar grains and high densities are promising candidates for solid-state refrigeration. In this work, the Cu₇₁Al_17.5Mn_11.5 alloys with a strong 〈001〉 texture columnar grains and a high relative density were fabricated using laser-based powder bed fusion of metals (PBF-LB/M) technique. The Cu₇₁Al_17.5Mn_11.5 alloys exhibited enhanced superelasticity, with a superelastic strain of 6.2 %. A maximum recoverable strain of 8.5 % was achieved under 9 % compressive loading, which includes both superelastic and elastic strain components. Additionally, a notable elastocaloric temperature change of 8.0 K was achieved upon fast unloading under adiabatic conditions. The phase transformation behavior has been systematically investigated by the digital image correlation (DIC) and the transmission wide-angle X-ray diffraction measurements. The current results suggest that the additive manufacturing could be a promising route for near-net-shape high-performance Cu-based elastocaloric refrigerants.