Enhanced Superelasticity and Notable Elastocaloric Effect of Cu71al17.5mn11.5 Shape Memory Alloys by Laser Powder Bed Fusion

Abstract

Cu-based shape memory alloys (SMAs) with highly oriented columnar grains and high densities become the candidate for solid-state refrigeration. In this work, the Cu71Al17.5Mn11.5 alloys with a strong <001> texture columnar grains and a high relative density have been directly printed by laser powder bed fusion (L-PBF) technique. The Cu71Al17.5Mn11.5 alloys exhibited enhanced superelasticity, with a superelastic strain of 6.2% and a maximum recoverable strain of 8.5% under 9% compressive loading. 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.

Keywords: Shape memory alloy, powder bed fusion, Cu-Al-Mn, Superelastic properties, Elastocaloric effect