Abstract—The effect of preliminary thermal cycling and annealing performed in the range of aging temperatures on the microstructure and mechanical behavior of a TiNi alloy is considered. The structure in the initial state consists of almost dislocation-free austenite grains. Equal-channel angular pressing results in an ultra-fine grained (UFG) structure consisting of equiaxed grains with an average size of 400 nm in the Ti₄₉Ni₅₁ alloy. The maximum number of thermal cycles is n = 100. The yield strength decreases when the number of thermal cycles increases to n = 100, which can be attributed to a saturation effect. The significant decrease in the yield strength at n = 100 can be associated with a high density of defects and aging particles, which cause the fracture of samples at lower tensile strength values, making dislocation motion difficult. Thermal cycling and subsequent annealing at 400°C do not change the grain size. The results of tensile tests show that thermal cycling (n = 100) and subsequent aging increase the tensile strength and yield strength in the UFG state.

摘要- 考虑了在时效温度范围内进行的初步热循环和退火对 TiNi 合金的微观结构和机械行为的影响。初始状态的组织由几乎没有位错的奥氏体晶粒组成。_{等通道角压制导致在 Ti 49} Ni ₅₁合金中由平均尺寸为 400 nm 的等轴晶粒组成的超细晶粒 (UFG) 结构。最大热循环次数为n = 100。当热循环次数增加到n = 100 时，屈服强度降低，这可归因于饱和效应。在n处屈服强度显着降低= 100 可能与高密度的缺陷和老化颗粒有关，这会导致样品在较低的拉伸强度值下断裂，从而使位错运动变得困难。热循环和随后的 400°C 退火不会改变晶粒尺寸。拉伸试验结果表明，热循环 ( n = 100) 和随后的时效提高了 UFG 状态下的拉伸强度和屈服强度。