Effect of annealing and deformation temperature on low-temperature superelasticity of Ti-Ni-Cr shape memory alloy springs
The low-temperature superelasticity of Ti-50.8Ni-0.3Cr alloy springs annealed at 350-800 ℃ during deformation in the temperature range of-20-20 ℃ was studied using tensile tests.The results show that when annealing in the temperature range of 350-800 ℃,as the annealing temperature increases,the external output stress of the alloy springs first decreases and then increases,and then tends to stabilize.When deformed within the temperature range of-20 to 20 ℃,as the deformation temperature increases,the external output stress of the alloy springs increases.To achieve superelasticity with smaller residual strain of the alloy spring at-20 ℃,it can be annealed at 350-400 ℃ or 550-800 ℃.To achieve superelasticity with smaller residual strain of the alloy spring at-10-20 ℃,it can be annealed at 350-500 ℃.To achieve high energy dissipation of the alloy spring at-20-20 ℃,it can be annealed at 450-800 ℃.As the annealing temperature increases,the strain recovery rate of the alloy springs decreases.As the number of stress-strain cycles increases,the strain recovery rate of the alloy springs first decreases and then tends to stabilize.Pre-cycle training can significantly improve the stability of the strain recovery rate of the alloy springs.
Ti-Ni-Cr alloyshape memory alloyspringsuperelasticityannealing temperaturedeformation temperature
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