【摘要】 通过熔炼、锻造、拔丝及退火工艺制备了纳米晶Ni₅₁Ti₄₆V₁Nb₂（%原子分数）合金丝材。利用透射电镜（TEM）观察了样品的微观组织结构，利用穿透式广角X射线衍射仪（WAXRD）、差示扫描量热仪（DSC）和电阻测试仪表征了样品的热致相变行为，利用万能拉伸试验机测试了样品在不同温度下的超弹行为。结果表明，丝材样品平均晶粒尺寸为46 nm,在降温过程中保持B2结构不变；样品在143～323 K温域内展现超弹性，临界相变应力的温度依赖性为2.2～5.0 MPa/K,且低温超弹回复率接近100%;样品的临界相变应力与应力滞后随室温加、卸载循环次数升高而略有下降，下降幅度与循环应变量有关。更多还原

【Abstract】 In this paper, nanocrystalline Ni₅₁Ti₄₆V₁Nb₂（at.%） alloy wire was prepared through the processes of smelting, forging, wire drawing and annealing. The microstructure of the sample was observed by transmission electron microscopy（TEM）. The thermally induced transformation behavior of the sample was characterized by in situ wide angle X-ray diffraction（WAXRD）, differential scanning calorimetry（DSC） and electrical resistance testing instrument. The superelastic behavior of the sample at different temperatures was tested by a universal tensile machine. Results show that the average grain size of the wire sample is 46 nm, and the B2 structure remains unchanged during the cooling processes. The sample exhibits superelasticity within the temperature range of 143-323 K. The temperature dependence of the critical transformation stress is the range of 2.2-5.0 MPa/K, and the low-temperature superelastic recovery rate is close to 100%. The critical transformation stress and stress hysteresis of the sample decrease slightly with the increase of the number of loading and unloading cycles at room temperature, and the decrease range is related to the cyclic strain amount.更多还原