Abstract The plastic deformation behavior under various strain-path changes in an A6022-T4 Al alloy sheet was studied, focusing on the evolution of the direction of the plastic strain rate θ and the stress ratio φ after abrupt strain-path changes. A cruciform specimen was used to measure the evolution of the plastic deformation behavior after abrupt strain-path change experimentally. Before the strain-path change, the deformation was represented well by the associated flow rule with the Yld2000-2d yield function and isotropic hardening assumption. After the abrupt path change, the deformation temporarily deviated from the associated flow rule, and it could be represented again by the associated flow rule after the plastic work increased roughly 4.0 MJ ⋅ m − 3 , which corresponded to the strain increment of approximately 0.024 under uniaxial tension in the rolling direction. The transitions of θ and φ as a function of plastic work showed that both θ and φ tend to converge to certain values regardless of the strain path if the final strain-path angles are identical. It was also found that the relationships between φ and θ temporarily deviate from the associated flow rule immediately after the abrupt path changes because φ cannot follow the rapid change of θ . Crystal plasticity finite-element simulations reproduced the qualitative tendencies observed in the experiments, but the deviations from the associated flow rule were much more pronounced. Parametric studies showed that φ tends to converge to different values depending on the strain rate sensitivity, whereas θ tends to converge to a same value irrespective of the rate sensitivity exponent. The rate sensitivity exponent m = 0.044 gave the best fits with the experimental results in terms of the evolution of both θ and φ under an abrupt change path, although the rate sensitivity exponent determined from macroscopic strass-strain curves were m = 0.002.

中文翻译：

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A6022-T4 铝合金板材应变路径变化时塑性变形行为的演变

摘要 研究了A6022-T4铝合金板材在各种应变路径变化下的塑性变形行为，重点研究了应变路径突变后塑性应变率θ和应力比φ方向的演变。十字形试样用于通过实验测量突然应变路径变化后塑性变形行为的演变。在应变路径变化之前，变形由具有 Yld2000-2d 屈服函数和各向同性硬化假设的相关流动规则很好地表示。在突然的路径变化之后，变形暂时偏离了相关的流动规则，在塑性功增加大约 4.0 MJ ⋅ m − 3 后，它可以再次由相关的流动规则表示，这对应于大约 0 的应变增量。024 在轧制方向的单轴张力下。作为塑性功函数的 θ 和 φ 的转变表明，如果最终应变路径角度相同，则无论应变路径如何，θ 和 φ 都倾向于收敛到某些值。还发现 φ 和 θ 之间的关系在突然路径变化后立即偏离了相关的流动规则，因为 φ 不能跟随 θ 的快速变化。晶体塑性有限元模拟再现了实验中观察到的定性趋势，但与相关流动规则的偏差要明显得多。参数研究表明，φ 趋向于收敛到不同的值，这取决于应变率敏感性，而 θ 趋于收敛到相同的值，而不管应变率敏感性指数如何。