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通过单轴拉伸试验研究工业纯钛在283~573 K下应变速率范围为0.000 05~0.005 s~(-1)的流动应力行为,确定工业纯钛应变速率敏感性及应变强化指数随温度的定量变化。结果表明:工业纯钛的应变速率敏感性在283~423 K不显著,应变强化指数在353~573 K随温度变化而增加。基于温度变化的修正型Fields-Backofen方程,建立了能够描述工业纯钛塑性流动应力行为的数学模型。同时,考虑应变、应变速率及温度之间的相互作用,对传统的Johnson-Cook方程进行改进。与传统的Johnson-Cook方程相比,改进型的Johnson-Cook方程与实验结果吻合更好,证明改进型Johnson-Cook方程预测工业纯钛塑性流动应力的精确性。
The uniaxial tensile test was used to study the flow stress behavior of industrial pure titanium at strain rates ranging from 0.0005 to 0.005 s ~ (-1) at 283-573 K and the strain rate sensitivity and strain hardening index Quantitative changes. The results show that the strain rate sensitivity of industrial pure titanium is not significant at 283 ~ 423 K, and the strain hardening index increases at 353 ~ 573 K with temperature. Based on the modified Fields-Backofen equation with temperature variation, a mathematical model capable of describing the plastic flow stress behavior of pure titanium was established. At the same time, the traditional Johnson-Cook equation is improved by considering the interaction between strain, strain rate and temperature. Compared with the traditional Johnson-Cook equation, the improved Johnson-Cook equation is in good agreement with the experimental results, which proves that the modified Johnson-Cook equation can predict the plastic flow stress of industrial pure titanium.