【摘要】 超低温加工技术可以有效改善钛合金加工过程中存在的切削温度高、加工质量差等问题，然而，钛合金低温本构模型的缺失制约了钛合金超低温加工技术的进一步发展。以TA15钛合金为研究对象进行低温静态拉伸试验，分析了TA15合金的低温力学性能，构建了钛合金低温本构模型，并基于不等分剪切区理论验证了本构模型的准确性。试验结果表明，在低温条件下，TA15钛合金的强度提高，延伸率和塑性降低，在-196℃时材料强化阶段明显缩短；将本构模型计算获得的切削力与试验获得的切削力对比研究发现，主切削力最大误差为22.34%,最小误差为0.48%,进给力最大误差为26.32%,最小误差为1.43%。修正后的Johnson-Cook本构模型具有较高的准确性，可以为钛合金超低温加工机理的研究提供参考和指导。更多还原

【Abstract】 The cryogenic machining technology can effectively improve the problems of high cutting temperature and poor machining quality in the titanium alloy machining process.However, the lack of cryogenic constitutive model of titanium alloy restricts the further development of cryogenic machining technology of titanium alloy.This paper takes TA15 titanium alloy as the research object, carries out cryogenic static tensile test, analyzes the cryogenic mechanical properties of TA15 alloy, constructs the cryogenic constitutive model of the alloy, and verifies the accuracy of the constitutive model based on the unequal shear zone theory.The results show that at low temperature, the strength of TA15 titanium alloy increases, the elongation and plasticity decrease, and the strengthening stage of the material is significantly shortened at-196℃.The comparison between the cutting force calculated by the constitutive model and the cutting force obtained by the test shows that the maximum error of the main cutting force is 22.34%,the minimum error is 0.48%,the maximum error of the feed force is 26.32%,and the minimum error is 1.43%.The modified Johnson-Cook constitutive model has high accuracy and can provide reference and guidance for the study of cryogenic machining mechanism of titanium alloys.更多还原