颗粒增强铝基复合材料热等静压近净成形有限元模拟

目的 建立可靠的模拟方法，以更高效地预测颗粒增强铝基复合材料(PRAMC)粉末热等静压中的形状变化和不同部位致密度的差异，解决传统实验试错方法适用性差且费时费力的问题，满足批量应用的需求。方法 以45%(体积分数)SiCp/6092Al复合材料为研究对象，构建了能预测粉末热等静压成形过程的有限元模型。使用Gurson-Tvergard-Needleman(GTN)模型作为粉末本构模型，建立了粉末尺度的代表性体积单元(RVE)对GTN模型进行修正。结果 通过对比GTN模型计算结果与实验结果，发现修正后的GTN模型能更准确地预测模型的最终变形尺寸，与修正前相比，相对误差降低了1.6%~2.9%。使用修正后的GTN模型对杯形回转体零件的热等静压成形过程进行预测，最终形状的计算结果与实验结果的相对误差仅为0.2%~3.1%，致密度分布的相对误差在0.5%以内。在探究包套厚度对热等静压过程的影响时发现，随着包套厚度的增大，热等静压过程中的屏蔽作用增强，内部粉体致密度下降。结论 为PRAMC热等静压近终形制备的形状和致密度控制问题提供了有限元预测工具，辅助优化了热等静压工艺和包套设计，降低了颗粒增强铝基复合材料热等静压近净成形过程开发的试错成本。

Finite Element Simulation of Near Net Shape Hot Isostatic Pressing of Particle Reinforced Aluminum Matrix Composites

The work aims to establish a reliable simulation method to predict shape changes and density differences in different components of particle reinforced aluminum matrix composite (PRAMC) during powder hot isostatic pressing more efficiently, so as to solve the problem of poor applicability and time-consuming efforts of trial errors in traditional experimental methods, and to meet the demands of batch application. A finite element model of the powder hot isostatic pressing forming process for 45vol.% SiCp/6092Al composite material was developed. With the Gurson-Tvergard-Needleman (GTN) model as the powder constitutive model, a representative volume element (RVE) was established to modify the GTN model. By comparing the computed results of the GTN model with experimental results, the modified GTN model accurately predicted the final deformation size of the model with a reduced relative error of 1.6%-2.9% compared to that before the modification. The modified GTN model was used to predict the hot isostatic pressing forming process of a rotary components, the final shape calculation result had a relative error range of only 0.2%-3.1% with the experimental result and the relative error of the density distribution was within 0.5%. In addition, the effect of sheath thickness on the hot isostatic pressing process was explored and it was found that as the encapsulated thickness increased, the encapsulated effect in the hot isostatic pressing process also increased, leading to a decrease in the internal powder densification. A finite element prediction tool was provided for the shape and density control of PRAMC near net shape forming, helps to optimize the hot isostatic pressing process and encapsulation design, and reduces the trial error cost of developing the near net shape process of PRAMC by hot isostatic pressing.