ABSTRACT

The composite components with complex-shape and containing different nanoparticle contents and sizes were successfully produced by the short-process thixoforming. Based on the developed constitutive model, numerical simulation of thixoforming for the composites with a high solid fraction was carried out, and the relevant experiments were performed. The influences of temperature and forming rate on strain-stress were analysed. Furthermore, the effects of temperature, moving rate of the die and holding time on the filling behaviour were discussed. Results of numerical simulation revealed that at high temperature and high forming rate, uniformly distributed stress-strain field and reduced maximum forming force could be obtained, which is advantageous for avoiding the non-uniform composition and incomplete filling caused by liquid-phase segregation; they were consistent with experimental results. After T6 heat treatment, the average yield strength and ultimate tensile strength of the parts were significantly improved. Moreover, the fracture mechanism of the part was discussed.

摘要

通过短流程触变性成功制备出形状复杂，纳米颗粒含量和粒径不同的复合材料。在建立的本构模型的基础上，对高固含量复合材料的触变性进行了数值模拟，并进行了相关实验。分析了温度和成形速率对应变应力的影响。此外，讨论了温度，模具移动速率和保持时间对填充行为的影响。数值模拟结果表明，在高温高成形速率下，应力-应变场分布均匀，最大成形力减小，有利于避免液相偏析引起的成分不均匀和填充不完全。它们与实验结果一致。经过T6热处理后，零件的平均屈服强度和极限抗拉强度得到了显着提高。此外，还讨论了零件的断裂机理。