Investigating stress-strain response in shape memory alloys
17 Jan 2019



In situ neutron diffraction was used to analyse stress-induced phase transformation.




​High-temperature shape memory alloys (HT-SMAs) have numerous potential applications, including as solid-state actuators or damping devices for high temperature use in the automotive and aerospace sectors. As conventional binary Ni–Ti SMAs only exhibit fully reversible transformations at temperatures up to about 100 °C, and suffer from microstructural instability, researchers have been investigating new alloys with enhanced properties. An international team of researchers used in situ neutron diffraction experiments on SXD, using a newly-installed testing setup on Co–Ni–Ga single crystals. Their aim was to reveal the nature of the stress–strain response seen in the deformation curves up to 10% macroscopic strain, and their results show that the martensite phase is able to withstand about 5% elastic strain, which significantly increases the overall deformation capability of this alloy system. 

Related publication: A Reul et al. “In Situ Neutron Diffraction Analyzing Stress-Induced Phase Transformation and Martensite Elasticity in [001]-Oriented Co49Ni21Ga30 Shape Memory Alloy Single Crystals" Shap. Mem. Superelasticity 4(2018), 61-69, DOI: 10.1007/s40830-018-0156-1​​

Contact: de Laune, Rosie (STFC,RAL,ISIS)