Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1644345 | Materials Letters | 2014 | 4 Pages |
•The thermal stability of Ni54Mn25Ga20.9Gd0.1 polycrystalline alloy with large reversible strain was investigated.•The transformation temperatures, martensitic structure and substructure did not change after 2000 thermal cycles.•This alloy displayed outstanding stability on shape memory effect due to high thermal stability of reversible martensitic transformation.•This alloy has excellent thermal stability which is similar to Ni54Mn25Ga21 single crystal.
The thermal stability of polycrystalline Ni54Mn25Ga20.9Gd0.1 high-temperature shape memory alloy was systematically investigated by the combination of X-ray diffraction, transmission electron microscopy, differential scanning calorimetry and compression tests. The results show that the non-modulated tetragonal martensite of structure and type I(111)M twin of substructure was unchanged even after 2000 thermal cycles, and some dislocation structures were formed in martensite of thermal-cycled alloy. The martensitic transformation temperatures after different thermal cycles have no difference, and the shape memory effect decreased from 7.5% to 7.4% due to formation of dislocation structures. The excellent thermal stability was ascribed to the single-phase and well self-accommodated martensitic twins.