高应变速率下45钢绝热剪切变形特征

基于退火、正火、调质三种不同热处理状态的45钢的帽型试样强迫剪切实验，在Hopkinson压杆的不同速率加载条件下，利用金相显微镜和扫描电镜测试方法研究了材料绝热剪切的变形特征和敏感性，分析了组织因素对绝热剪切的影响规律。结果表明，材料的组织不同，其绝热剪切变形的特征也不同。45钢正火态、调质态中均出现转变带，其余为形变带。随着加载速率和材料强度的提高，绝热剪切带由形变带变为转变带，剪切带宽度越窄，绝热剪切越敏感。

Adiabatic Shearing Deformation Characteristics of 45 Steel at High Strain Rates

The adiabatic shearing deformation characteristics of 45 steel in three kinds of heat-treated conditions, including annealing, normalizing and modified treatment, was investigated under forced shearing test using hat-shaped specimens by means of the Split Hopkinson Pressure Bar （SHPB）. The adiabatic shearing sensitivity and deformation characteristic of material were studied by using MetaUographic microscope and Scanning electronic microscope （SEM）. The effect of structure on the adiabatic shearing was discussed in detail. It is found that, materials with different texture have different adiabatic shearing deformation characteristics. Transformation band appears in normalizing and modified treated materials, and deformed band appears in the other materials. The adiabatic shear band changed from deformation band to transformation band with the elevation of loading rate and strength of 45 steel, the narrower the width of the shear band is, the more sensitive the shear band is.