Unlocking Enhanced Thermal Management with High-Performance Shape Memory Alloys

Shape memory alloys (SMAs) are gaining increasing attention as phase change materials (PCMs) owing to their solid-to-solid martensitic phase transformation. Compared to conventional PCMs used in thermal energy storage (TES) applications, SMAs exhibit a combination of high density and 1-2 orders of magnitude greater thermal conductivity values making them ideal material choices for applications where fast transient thermal transport is required. SMAs can also operate over a wide range of temperatures and can be tailored to specific operational temperature ranges (OTR) through composition and processing control. This study showcases the effectiveness of various SMA systems in thermal management and highlights the unique characteristics of different alloys as PCMs. Experimental investigations and an artificial intelligence materials selection framework were applied to NiTiHf, NiTiCu, and CuZnAl SMAs to select compositions with high Figure of Merit (FOM) values, quantifying the TES performance. NiTiHf alloys exhibited a 120% higher FOM than binary NiTi alloys and have transformation temperatures exceeding 500°C, expanding the range of high FOM PCMs. NiTiCu alloys boast a high FOM and an ultra-low OTR (12-20°C), in contrast to NiTi and NiTiHf SMAs (~50°C), making them suitable for applications with narrow temperature restrictions. CuZnAl alloys also offer high FOM values, primarily due to their excellent thermal conductivity, making them ideal for applications where the rate of thermal transfer is critical.