预变形温度对Ni47Ti44Nb9合金Φ8mm管接头恢复性能的影响
Effect of Pre-deformed Temperature on Recovery Property of Ni47Ti44Nb9 Alloy Φ8mm Pipe Joint
-
摘要: 采用低温扩径、水浴加热等方法,研究了预变形温度对Ni47Ti44Nb9合金Φ8mm管接头恢复性能的影响。结果表明:在预变形温度为-55℃~-90℃范围内,Φ8mm管接头内径处的相变滞后,径向剩余应变随预变形温度的升高先增大后减小;在预变形温度为-65℃时,内径处相变滞后和径向剩余应变分别得到最大值122℃和1.3%;内径处的弹性应变、径向可恢复应变和恢复率随着预变形温度的升高先减小后增大,其中内径处弹性应变在-65℃时得到最小值1.0%,径向可恢复应变和恢复率在-65℃时分别达到8.6%和86.5%。为获得宽的相变滞后和大的恢复力,Φ8mm管接头的最佳预变形温度为-65℃。Abstract: The effect of pre-deformed temperature on memory recovery properties of Ni47Ti44Nb9 alloy pipe joints was studied by using the methods of expanding diameter at low temperatures and water bath heating. The results showed that the transformation hysteresis and residual strain in internal diameter of Φ8mm pipe joints increased firstly and then decreased with the rise of the pre-deformed temperature in the pre-deformed temperature range of-55~-90℃. Transformation hysteresis and residual strain reached the maximum values 122℃ and 1. 3% respectively when the pre-deformed temperature is-65℃. At the same time,the elastic strain of inner diameter,radial recoverable strain and recovery rate decreased firstly and subsequently increased with the rise of the pre-deformed temperature. Consequently,the elastic strain reached the minimum value 1. 0% at the pre-deformed temperature-65℃. Otherwise, the radial recoverable strain and recovery rate can get the higher value 8. 6% and 86. 5% respectively,when the pre-deformed temperature is-65℃. Conclusion demonstrated that in order to obtain the wide transformation hysteresis and high recovery stress,the optimum pre-deformed temperature of Φ8mm pipe joint should be determined as-65℃.