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为了了解V-5Cr-5Ti合金(质量分数)热加工过程的基本物理机制,在Gleeble-3800热物理模拟试验机上采用热压缩方法测量合金在1373~1673K范围内的热激活参数。结果表明:抛物线型本构方程的应力指数n和激活能Q分别为4.87和375.89kJ/mol。通过引入临界应力参数(σ_0),计算得到的激活能Q为288.34 kJ/mol,这与合金的自扩散激活能(270~300kJ/mol)相近。重复应力松弛实验得到合金的物理激活体积V_p和应变速率敏感指数m分别为(120~700)b~3和0.075~0.122。上述激活参数表明:V-5Cr-5Ti合金在1373~1673K和0.001~1.0s~(-1)范围内的热压缩物理机制为克服林位错钉扎的位错攀移。
In order to understand the basic physical mechanism of thermal processing of V-5Cr-5Ti alloy (mass fraction), the thermal activation parameters of alloy in the range of 1373 ~ 1673K were measured by hot compression method on Gleeble-3800 thermal physical simulation tester. The results show that the stress index n and activation energy Q of the parabolic constitutive equation are 4.87 and 375.89 kJ / mol, respectively. By introducing the critical stress parameter (σ_0), the calculated activation energy Q is 288.34 kJ / mol, which is close to the self-diffusion activation energy of the alloy (270-300 kJ / mol). Repeated stress relaxation experiments show that the physical activation volume V_p and the strain rate sensitivity index m of the alloy are (120 ~ 700) b ~ 3 and 0.075 ~ 0.122, respectively. The above activation parameters indicate that the physical mechanism of thermal compression of V-5Cr-5Ti alloy in the range of 1373 ~ 1673K and 0.001 ~ 1.0s ~ (-1) is to overcome the dislocation climbing caused by forest pinning.