铝合金板材塑性性能的研究

铝合金在汽车工业中的广泛应用对于降低汽车重量、减少燃油消耗和汽车尾气的排放量具有十分重要的意义，但其室温塑性成形性能却受到了锯齿形屈服行为的影响，从而制约了铝合金进一步的推广应用。本文基于合金材料塑性变形过程中位错和溶质原子间相互作用的分析，建立了一个可用于描述锯齿形屈服现象的唯象本构模型。该模型将溶质原子对位错运动的钉扎效应和位错挣脱后的脱钉效应置于一个统一的框架内进行考虑，而这两个效应的相互竞争将决定材料宏观变形行为的发展演化。基于该模型的数值模拟结果和实验测试结果取得了良好的一致性，从而验证了理论和模型的有效性。

On the Plastic Properties of Al Sheet Materials

The wide use of Al alloys in the automotive industry has great significance to lighten the weight of automobile, and therefore will contribute to diminishing vehicle running costs and reducing tail gas generation. However, the plastic formability of Al sheet materials at room temperature is greatly decreased by the serrated yielding phenomenon, which limits their further application. A phenomenological model was developed to investigate the mechanical behavior related to serrated yielding, based on the analysis of the interaction between dislocation and solute atoms during plastic deformation. The pinning effect of solute atoms on dislocation movement and its counterpart, the depinning effect of dislocation slipping out of the solute atmosphere, were considered in a unified scheme, and thus the evolution of macroscopic deformation will be determined by the competition of these two effects at the micro level. The modeling results were found in good agreement with the experimental data, which verifies the applicability of the established model.