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研究了U-2.5%Nb合金在-100～700℃温度范围内的力学性能。结果表明,合金的抗拉伸强度随试验温度上升呈下降趋势,其塑性在600℃以下温度并非单调变化,而是在500℃附近延伸率和断面收缩率分别出现极小值,合金拉伸断口与室温(20℃)相比具有明显的沿晶断裂特征。试验温度高于600℃后,合金塑性明显升高。热处理后的该合金加热至500℃经保温并冷至室温后,合金的冲击韧性有所降低。在-100℃～室温的温度范围,合金的冲击韧性随试验温度的降低而下降,并在-30～-10℃的温度范围发生韧脆转变。当温度低于-30℃后冲击韧性下降趋势明显减缓,合金冲击断裂面颗粒高低不平,具有准解理断裂特征。
The mechanical properties of U-2.5% Nb alloy at -100 ~ 700 ℃ were studied. The results show that the tensile strength of the alloy decreases with the increase of the test temperature. The ductility of the alloy does not change monotonically at the temperature below 600 ℃, but the elongation and the reduction of area at the temperature of 500 ℃ show minimum values respectively. Compared with room temperature (20 ℃) has obvious intergranular fracture characteristics. After the test temperature is higher than 600 ℃, the plasticity of the alloy is obviously increased. After heat treatment of the alloy heated to 500 ℃ after insulation and cooled to room temperature, the impact toughness of the alloy decreased. In the temperature range from -100 ℃ to room temperature, the impact toughness of the alloy decreases with the decrease of the test temperature and the ductile-to-brittle transition occurs in the temperature range from -30 ℃ to -10 ℃. When the temperature is lower than -30 ℃, the tendency of the impact toughness decreases obviously. The particles on the impact fracture surface of the alloy have the characteristics of quasi-cleavage fracture.