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在THERMECMASTOR-Z型热模拟机上对Ti-6.5Al-3.5Mo-1.5Zr-0.3Si合金在变形温度780～1080℃,应变速率0.001～70.000s-1条件下的流动应力变化规律进行了研究,分析了变形工艺参数对Ti-6.5Al-3.5Mo-1.5Zr-0.3Si合金绝热剪切和局部流动行为的影响,并采用基于动态材料模型的功率耗散图分析了Ti-6.5Al-3.5Mo-1.5Zr-0.3Si合金易发生绝热剪切和局部流动的热力参数范围。结果表明:在所研究的热变形条件下,当温度较高、应变速率较低时,变形呈稳态流动特征,当温度较低、应变速率较高时,变形呈流动软化特征。通过功率耗散图分析及微观组织观察可知,在α+β两相区变形,应变速率高于0.100s-1时,功率耗散系数多数小于0.16,变形多处于流变失稳区域,其变形机制主要为绝热剪切和局部流动。
The variation of flow stress of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy at deformation temperature of 780 ~ 1080 ℃ and strain rate of 0.001 ~ 70.000s-1 was studied on THERMECMASTOR-Z thermal simulator. The influence of deformation parameters on the adiabatic shear and local flow behavior of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy was analyzed. The power dissipation diagram based on the dynamic material model was used to analyze the Ti-6.5Al-3.5Mo -1.5Zr-0.3Si alloy prone to adiabatic shear and local flow of thermal parameters of the range. The results show that when the temperature is high and the strain rate is low, the deformation is a steady flow under the hot deformation conditions studied. When the temperature is lower and the strain rate is higher, the deformation is flow softening. According to the analysis of power dissipation diagram and microstructure observation, it can be seen that the power dissipation coefficient is mostly less than 0.16 when the deformation rate is higher than 0.100s-1 in the α + β two-phase zone and the deformation is mostly in the rheological instability zone. The mechanism is adiabatic shear and local flow.