含Sc超高强Al-Zn-Cu-Mg-Sc-Zr合金的热压缩变形流变应力

来源期刊:中国有色金属学报2008年第5期

论文作者:李文斌 潘清林 梁文杰 何运斌 刘俊生 李运春

文章页码:777 - 777

关键词:Al-Zn-Cu-Mg-Sc-Zr合金;热压缩变形;流变应力;Zener-Hollomon参数;热变形激活能

Key words:Al-Zn-Cu-Mg-Sc-Zr alloy; hot compression deformation; flow stress; Zener-Hollomon parameter; hot deformation activation energy

摘    要:

采用Gleeble1500热模拟机在应变速率为0.001~10 /s、温度为380~470 ℃、真应变为0~0.7的条件下,研究了实验合金的流变应力行为。结果表明:该合金热压缩变形时存在较明显的稳态流变特征,当<1 /s时,流变应力开始随应变增加而增加,达到峰值后趋于平稳,呈动态回复特征;当≥1 /s时,流变应力均出现了明显的峰值应力,为连续动态再结晶特征。带Zener-Hollomon参数的双曲正弦函数可描述合金高温变形时的流变应力,σ解析表达式中A、α和n值分别为5.952×108 /s、0.021 MPa-1和5.397;热变形激活能Q为157.9 kJ/mol。

Abstract:

The flow stress of the studied alloy over the strain rate of 0.001-10 /s, the temperature of 380-470 ℃ and true strains of 0-0.7 was studied on Gleeble-1500 hot simulator. The experimental results show that the steady-state flow characteristics exist during hot compression deformation in the range of experiments. At lower strain rates(<1 /s), the flow stress increases with the increase of strain, then keeps steady and shows dynamic recovery. At high strain rates(≥1/s), the flow stress decreases after the flow stress reaches obvious peak value with the increase of strain and shows dynamic recrystallization. The flow stress of the alloy during high temperature deformation can be represented by a Zener-Hollomon parameter in the hyperbolic Arrhenius-type equation. Structure factor A, stress level parameter α and stress index n in the analytical expressions of σ are turned to be 5.952×108 /s, 0.021 MPa-1 and 5.397. The average hot deformation activation energy of the alloy is 157.9 kJ/mol.

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