高体积分数TiB2/Al复合材料的动态压缩性能

Dynamic Compression Properties of TiB2/Al Composites

摘要:

采用分离式霍普金森压杆(SHPB)研究高体积分数TiB2/Al复合材料(55%-65%)的动态压缩性能，并对其在高应变率下的损伤机制进行分析。结果表明，相比应变率不敏感的基体合金，高体积分数TiB2/Al复合材料表现出明显的应变率敏感性；且随着体积分数的增加，其应变率敏感系数和流动应力值表现出先升后降趋势。在高应变率冲击下，复合材料表现为脆性断裂，增强相含量越高复合材料越易剪切破坏。复合材料断面局部呈现熔融铝团，直径为50~200 μm，这与绝热温升效应有关。绝热温升使得基体合金软化，有效缓解高体积分数复合材料的瞬态失稳破坏

Abstract:

Dynamic compression properties and adiabatic shear behavior of TiB2/Al composites (55%-65%, volume fraction) were investigated by split Hopkinson pressure bar (SHPB). The instantaneous failure of the composite was ascribed to the formation of adiabatic shear band when compressed. It is found that the composites tend to adiabatic shear failure as the reinforcement content increases. The flow stress and strain rate sensitivity exhibit rise/fall tendency with the increasing of strain rates. Additionally, the plastic deformation ability of the composites at high strain rates is highly improved. All the composites were failed in brittle fracture, which is controlled by the breaking of reinforcement particles and splitting of TiB2-Al interfaces