热压缩2519 铝合金流变应力特征

采用Gleeble-1500 热模拟机进行高温等温压缩试验, 研究了2519 铝合金在高温塑性变形时的流变应力特征。试验温度为300～500 ℃、应变速率为0.05～25 s^-1 。实验结果表明:2519 铝合金真应力-应变曲线在低应变速率(﹒ε≤25 s^-1)条件下, 流变应力开始随应变增加而增大, 达到峰值后趋于平稳, 表现出动态回复特征;而在高应变速率(﹒ε≥25 s^-1)条件下, 应力出现锯齿波动达到峰值后逐渐下降, 表现出不连续再结晶特征;应变速率和流变应力之间满足双曲正弦关系, 温度和流变应力之间满足Arrhenius 关系;可用包含Arrhenius 项的Zener-Hollomon 参数来描述2519 铝合金高温压缩变形时的流变应力行为。

Feature of Flow Stress of 2519 Aluminum Alloy During Hot Compressive Deformation

The flow stress features of 2519 aluminum alloy during plastic deformation at elevated temperature were studied by the isothermal compression test using Gleeble-1500 hot simulator.The compression test was performed in the temperature range from 300 ℃ to 500 ℃and in the strain rate range 0.05 s^-1 to 25 s^-1.The experimental results show that the flow stress of 2519 aluminum alloy increased with increasing strain and tended to be constant after a peak value at lower strain rates (﹒ε≤25 s^-1), showing dynamic recover.The flow stress sawtooth fluctuated and decreased after a peak value with the increasing strain at higher strain rates(﹒ε≥25 s^-1), showing discontinuous dynamic recrystallization.A hyperbolic sine relationship was found to correlate well the flow stress with the strain rate, and an Arrhenius relationship with the temperature.The flow stress of 2519 alloy during high temperature deformation can be represented by Zener-hollomon parameter including the Arrhenius term.