A study on TiNi(Fe,Mo) shape memory alloy

The influences of Mo on the phase transformation, microstructure and mechanical behavior of TiNi(Fe) shape memory alloy are investigated by differential scanning calorimetry, X-ray diffraction, and tensile stress–strain measurements. The results show that the lattice parameter of TiNi(Fe,Mo) increases with progressing replacement of Ni by Mo, while the martensitic transformation characteristic temperatures decrease simultaneously. The yield strength of TiNi(Fe) alloys has been remarkably improved by addition of Mo, e.g. Ti50Ni47Fe2Mo1 alloy (at.%) shows a yield strength of 400 MPa, which is 33% higher than that of Ti50Ni48Fe2. Moreover, the martensite reorientation stress of Ti50Ni47Fe2Mo1 is 250 MPa at liquid nitrogen temperature and a shape memory effect of 6.4% has been achieved.