中文摘要：

在25-450℃内，沿轧向及横向研究了Ni47Ti44-Nb9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，这是由于不同的解挛晶机制造成的。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Ni47TLaNb9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。

英文摘要：

Ni47Ti44Nb9 shape memory alloy was studied by high temperature tensile experiments at 25-450 ℃ along the rolling and the transverse directions, respectively. The experimental results show that： the stress-plateau in the stress-strain curve appears along the rolling direction at 25 ℃. While, along the transverse direction, the stress-plateau disappears at 25 ℃. It is due to the different detwinning mechanism. With the increasing temperature to 100 ℃ and 300 ℃, the yield strength increases and maximum strain decreases, which indicate that the alloys become hard and brittle at those temperatures. With the temperature increasing to 450 ℃, the tensile strength drops rapidly and the maximum strain raises again, which can reveal that the alloys become soft and viscous.