振动时效在铝合金厚板应力消减中的局限与应用

Application of VSR technique in stress reduction of aluminum alloy thick plate and its limitation

运用振动时效对材料应力消减的作用,结合铝合金厚板残余应力消减后的分布及效果,认为振动时效对厚板结构残余应力消减作用有限。而运用位错理论和最小能量法分析,发现振动时效对材料因内部微结构差异而形成应力集中区域的应力松弛释放有所贡献,在一定激振频率和时效时间条件下,完全可以造成材料局部的微屈服,减小了微结构间残余应力水平,从而对板内应力的均匀化过程起到一定效果。借助实验对厚板振动时效前后表面应力强度和板形尺寸稳定性对比发现,振动时效对稳定板形和消减大梯度表面残余应力具有显著作用。

Usually, it is recognized that for thick plates VSR （vibratory stress relief） plays a limited role in the structural residual stresses relaxation. But, energy analysis in accordance with the dislocation theory proves that VSR has certain effect on stress relief of stress concentration regions caused by material internal micro-structure defects. Under certain excitation frequency and excitation time duration, VSR can homogenize the intra-plate stresses, since micro-yield of material local regions reduces residual stress level in micro-regions. Experimental results show that VSR has obvious effects on stabilization of shape and relaxation of surface residual stresses with a great gradient in thick plates.