Ni-Mn-Ga high-temperature shape memory alloys

作者：Xu H B^*; Li Y; Jiang C B

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2006, 438: 1065-1070.

DOI：10.1016/j.msea.2006.02.187

• NiMnGa
• shape memory alloy
• martensitic transformation
• grain refinement
• Fe alloying

The relationship among the composition, structure and martensitic transformation temperatures have been studied in detail for Ni50-xMn25Ga25-x, (at.%) alloys by optical and transmission election microscopy, X-ray diffraction and differential scanning calorimeter measurements. The martensitic transformation temperatures almost linearly increase with increasing Ni content up to 670 K showing their potentials as high-temperature shape memory alloys. The results show that the tetragonality ratio (c/a) increases with the Ni substitution for Ga, but the unit-cell volume reduces simultaneously. The martensitic transformation characteristics of Ni54Mn25Ga21 alloy with single martensite phase show excellent stability during thermal cycles or aging. The polycrystalline Ni54Mn25Ga21 alloy exhibited a shape-memory effect of 4.2% and compressive strain larger than 10% by using grain refining technique. Addition of Fe as a fourth element is an effective method to improve the mechanical properties, especially plasticity of polycrystalline Ni-Mn-Ga alloy due to the precipitation of gamma-phase. A compressive strain of 30% and a shape-memory effect of 2.8% are obtained for Ni56Mn17Fe8Ga19 alloy.

• 出版日期2006-12-25
• 单位北京大学