This letter reports on stress–strain experiments on a Cu – Zn – Al single crystal performed using a purpose-built tensile device which enables the load applied to the specimen to be controlled while elongation is continuously monitored. From the measured isothermal tensile curves, the stress-induced entropy changes are obtained at different temperatures. These data quantify the elastocaloric effect associated with the martensitic transition in shape-memory alloys. The large temperature changes estimated for this effect, suggest the possibility of using shape-memory alloys as mechanical refrigerators.