论文部分内容阅读
采用再结晶与重熔法(RAP)制备一种Al-Cu-Mg-Mn合金(2024)半固态坯料,研究间接触变成形过程中的显微组织演变和偏析行为。结果表明:对商用挤压态2024铝合金进行二次重熔处理,可以直接得到具有细小球晶组织的半固态坯料。在间接触变成形过程中增加底部区域厚度可以得到更好的应力分布状态。在三向压应力条件下,构件不同区域的显微组织较为均匀,没有发现明显的固液偏析和微观缩孔,而且柱体处的晶粒产生了明显的塑性变形。构件不同位置的力学性能和显微组织呈现出良好的对应关系。此外,还讨论了成形过程中的变形机制分布规律,并且提出了一种优化成形应力分布状态的工艺方法。
A semi-solid Al-Cu-Mg-Mn alloy (2024) billet was prepared by recrystallization and remelting (RAP) to study the microstructure evolution and segregation behavior during indirect thixoforming. The results show that semi-solid billets with fine spherulitic structure can be directly obtained by remelting the commercial extruded 2024 aluminum alloy. Increasing the thickness of the bottom area during indirect thixoforming results in a better stress distribution. Under the condition of three-dimensional compressive stress, the microstructures of different parts of the structure are more uniform, no obvious solid-liquid segregation and microcosmic shrinkage are found, and the grains at the column have obvious plastic deformation. The mechanical properties and the microstructure of the different parts of the structure showed a good correspondence. In addition, the distribution of deformation mechanism in the forming process is also discussed, and a process method for optimizing the forming stress distribution is proposed.