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应用材料试验机及霍普金森压杆装置(SHPB)对切削用置氢TC4钛合金进行了静态和动态压缩实验,获得了不同温度和应变率下的应力-应变曲线。实验中应变率范围为0.001～15000s-1,温度范围为293～973K。分析比较了合金流变应力对温度及应变率的敏感性。结果表明,置氢TC4钛合金具有较强的热软化效应,而应变率强化效应则相对较弱。随氢含量的增加,流变应力呈现先减小后增大的规律,氢含量0.3%时,最大降幅达25%。根据流变应力的变化规律及相关切削理论,对实验中切削力及切削温度的变化情况进行了分析。最后基于Johnson-Cook本构模型,拟合了模型中的参数,其预测值与实验结果吻合较好。
The static and dynamic compression experiments of TC4 titanium alloy for cutting were carried out by using material testing machine and Hopkinson pressure bar device (SHPB). The stress-strain curves under different temperature and strain rate were obtained. The experimental strain rate range of 0.001 ~ 15000s-1, the temperature range of 293 ~ 973K. The sensitivity of alloy flow stress to temperature and strain rate was analyzed and compared. The results show that the TC4 titanium alloy has strong thermal softening effect, while the strain rate strengthening effect is relatively weak. With the increase of hydrogen content, the flow stress decreases first and then increases, and the maximum decrease of 25% when the hydrogen content is 0.3%. According to the variation law of flow stress and the related cutting theory, the change of cutting force and cutting temperature in the experiment were analyzed. Finally, based on the Johnson-Cook constitutive model, the parameters in the model are fitted, and the predicted values are in good agreement with the experimental results.