论文部分内容阅读
在25～450℃内,沿轧向及横向研究了Ni47Ti44Nb9形状记忆合金的高温拉伸力学性能。结果表明:在室温下,沿轧向拉伸时出现了明显的应力平台,而沿横向拉伸则无此现象,这是由于不同的解孪晶机制造成的。当温度升高至100、300℃时,屈服强度增加,而断裂时的最大应变减小,在此温度下Ni47Ti44Nb9合金变得更加硬而脆。随温度进一步升高到450℃,Ni47Ti44Nb9合金的抗拉强度迅速减小,断裂时的最大应变再次增加,这表明此时合金变软,粘性增强。
The tensile mechanical properties of Ni47Ti44Nb9 shape memory alloy at 25 ~ 450 ℃ were studied along the rolling direction and the transverse direction. The results show that a significant stress plateau appears at room temperature when stretched in the rolling direction, but not in the transverse direction. This is due to different de-twinning mechanisms. As the temperature increases to 100,300 ° C, the yield strength increases and the maximum strain at break decreases, at which Ni47Ti44Nb9 alloy becomes harder and more brittle. With further increase of temperature to 450 ℃, the tensile strength of Ni47Ti44Nb9 alloy decreases rapidly and the maximum strain at fracture increases again, which indicates that the alloy softens and the viscosity increases at this time.