Microstructure, mechanical properties and shape memory effect of Ni–Mn–Ga–B high-temperature shape memory alloy

• The effects of boron addition on the properties of NiMnGaB HTSMA were investigated.
• Boron addition refined the grain and enhanced the mechanical properties of NiMnGaB alloys.
• The maximum SME value of 6.8% was obtained in (Ni54Mn25Ga21)99.5B0.5 alloy with pre-stain of 10%.

The effects of boron addition on the microstructure, transformation temperature, mechanical properties and shape memory effect of (Ni54Mn25Ga21)100−xBx alloys were investigated. The results showed that the martensitic transformation start temperatures Ms decreased monotonically from 465 K for x = 0–278 K for x = 3. Boron addition refined the grain and significantly enhanced the mechanical properties. The compressive fracture strain of 22.3% and reversible strain of 6.8% were obtained in (Ni54Mn25Ga21)99.5B0.5 alloy.