7075Al/SiCp复合材料的热压缩变形流变应力和组织行为

Flow Stress and Structure Behavior of 7075Al/SiCp Composites during Hot Compression Deformtion

采用圆柱试样在Gleeble-1500热模拟机上对喷射沉积7075Al／SiCp复合材料进行高温压缩变形实验，实验条件为：变形温度300-450℃，应变速率0．001～1s^-1。结果表明：7075Al／SiCp复合材料的流变应力大小受到变形温度和应变速率的强烈影响，流变应力随应变的增加而逐渐增加，出现一峰值后逐渐下降；流变应力随变形温度的升高、应变速率的降低而降低。可用Zener-Hollomon参数的双曲正弦形式来描述7075Al／SiCp复合材料高温压缩变形流变应力。随着变形温度的升高和应变速率的降低，7075Al／SiCp复合材料热变形过程中SiCp的分布逐渐均匀化，有利其热加工性能的改善。

The experiment of spray deposition 7075Al/SiCp composites during high temperature compression deformation is carried on Gleeble-1500 hot simulator using isothermal compression of cylindrical specimens, the deformation temperature vary from 300℃ to 450℃ ,strain rate from 0. 001s^-1 to 1s^-1. The experimental results show that the flow stress is controlled by both strain rate and deformation temperature , the flow stress values increase with the increase of strain, then decrease after a peak value~ the flow stress values decrease with the increase of temperature and the decrease of strain rate. The flow stress of 7075Al/SiCp composites during high temperature deformation can be represented by a Zener-hollomon parameter in a Sinh form. With the increasing deformation temperature and decreasing strain rate, the SiCp distributing in 7075Al/SiCp composites becomes more uniform. This indicates that hot workability of the 7075/SiCp pcomposite may be improved.