钛合金绝热剪切带宽度的演变规律研究

根据梯度增强的Johnson-Cook模型,对Ti-6Al-4V绝热剪切带中心区域的宽度(绝热剪切带宽度w5%)随平均塑性剪切应变的演变规律进行了预测。结果表明,随着平均塑性剪切应变的增加,w5%先是快速减小,然后趋于稳定。当绝热剪切带总宽度为0.3235mm时,w5%的稳定值接近Ti-6Al-4V绝热剪切带宽度的上限(55μm);当绝热剪切带总宽度为0.0705mm时,w5%的稳定值接近Ti-6Al-4V绝热剪切带宽度的下限(12μm)。绝热剪切带宽度受多种因素影响,例如,材料特性、加载速度、环境温度、应力及应变状态。本文的分析是在绝热条件下进行的,不存在塑性功率与热传导达到平衡(稳态)的假定。

Study on Evolution of Adiabatic Shear Band Width of Titanium Alloy

According to the gradient-enhanced Johnson-Cook model to investigate the evolution of the ASB width (w5%) with the average plastic shear strain for Ti-6Al-4V alloy. Results show that w5% decreases rapidly and then approaches a constant with the increasing of average plastic shear strain. When the total width of the ASB is 0.3235 mm, the critical value of w5% approaches the upper bound (55 μm) measured for Ti-6Al-4V, while when the total width of the ASB is 0.0705 mm, the critical value of w5% approaches the lower bound (12 μm). It is found that the ASB width is influenced by many factors such as material properties, loading rate, ambient temperature, stress and strain states. In the paper, the key assumption of the balance of heat diffusion and plastic work is not adopted and the present analysis is in adiabatic condition.