SiCp/2024Al复合材料高应变率热变形行为的新本构模型#br#

通过分离式霍普金森压杆(SHPB)动态压缩试验研究了体积分数为45%的铝基碳化硅颗粒增强复合材料（SiCp/2024Al）在大应变率和变形温度范围内的热变形行为，分析了热变形参数（变形温度和应变率）对流动应力的影响。研究发现：变形温度和应变率对复合材料的流变应力、抗压强度、弹性模量、应变率敏感性有显著影响；抗压强度、弹性模量随变形温度的增大而减小，而抗压强度、弹性模量、应变率敏感性随应变率的增大出现了拐点。根据试验结果，结合热力学和统计损伤力学理论，建立了描述SiCp/2024Al复合材料动态热变形行为的连续损伤本构模型，预测的流动应力与试验结果吻合较好，表明所建立的模型能够准确地描述SiCp/2024Al复合材料动态热变形行为。

A New Constitutive Model for Hot Deformation Behavior of SiCp /2024Al Composites under High Strain Rate#br#

Through the dynamic compression tests of the split Hopkinson pressure bar(SHPB), the thermal deformation behavior of the aluminum-based silicon carbide particle reinforced composite(SiCp/2024Al) with a volume fraction of 45% in a large strain rate and deformation temperature range was studied. The influence of thermal deformation parameters(deformation temperature and strain rate) on flow stress is analyzed. It is found that the deformation temperature and strain rate have significant effects on the flow stress, compressive strength, elastic modulus, and strain rate sensitivity of the composites. The compressive strength and elastic modulus decrease with the increase of deformation temperature, while the compressive strength, elastic modulus and strain rate sensitivity show an inflection point with the increase of strain rate. According to the experimental results, combined with thermodynamics and statistical damage mechanics theory, a continuous damage constitutive model describing the dynamic thermal deformation behavior of SiCp/2024Al composites was established. The predicted flow stress is in good agreement with the experimental ones, indicating that the model established may accurately describe the dynamic thermal deformation behavior of SiCp / 2024Al composites.