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采用改进静滴法测定了1773~1873K温度范围内熔融Ni-(5~10)W(质量分数,%)合金在Al2O3基板上于Ar+3%H2气氛下的表面张力数据。熔融Ni-W合金的表面张力随着温度的升高而降低。在此基础上采用Butler模型推导了表面张力随温度与浓度的变化情况,计算了合金体系中元素的偏聚情况。表面张力的计算结果与测量值的符合度较高。W在合金表面的浓度低于体相浓度。用Gleeble-1500型热模拟试验机对Ti53311S钛合金在温度为880~1080℃,应变速率为0.001~10s-1的条件下进行高温压缩变形行为的研究。测试了其真应力-真应变曲线,采用双曲正弦本构方程计算出激活能,双相区为641kJ/mol,β相区为244kJ/mol。观察了变形后的显微组织,并分析了其变形机制。结果表明:该合金对温度和应变速率敏感,不同变形条件下应力值变化很大;应变速率敏感指数(m)随温度升高而降低,而变形激活能(Q)随温度升高而增大。合金的变形机制在双相区为晶界滑移和晶粒球化,在β单相区为动态回复。
The surface tension data of molten Ni- (5 ~ 10) W (mass fraction,%) alloy on Al2O3 substrate under Ar + 3% H2 atmosphere were measured by the modified drop method in the range of 1773 ~ 1873K. The surface tension of molten Ni-W alloy decreases with increasing temperature. On this basis, the variation of surface tension with temperature and concentration was deduced by the Butler model, and the segregation of elements in the alloy system was calculated. The calculated results of surface tension are in good agreement with the measured values. W in the alloy surface concentration lower than the bulk concentration. The deformation behavior of Ti53311S titanium alloy at high temperature of 880 ~ 1080 ℃ and strain rate of 0.001 ~ 10s-1 was studied by Gleeble-1500 thermal simulation machine. The true stress - true strain curve was tested. The activation energy was calculated using the hyperbolic sine constitutive equation. The activation energy was 641 kJ / mol in the two - phase region and 244 kJ / mol in the β phase region. The deformed microstructure was observed and its deformation mechanism was analyzed. The results show that the alloy is sensitive to temperature and strain rate, and the stress value varies greatly under different deformation conditions. The strain rate sensitivity index (m) decreases with increasing temperature, while the deformation activation energy (Q) increases with increasing temperature . The deformation mechanism of the alloy is grain boundary slip and grain spheroidization in the two-phase region, and is a dynamic response in the single-phase region of β.