5A90铝锂合金电子束焊焊板超塑性变形力学行为

Superplastic deformation behavior of electron beam welded 5A90 aluminum lithium alloy

关键词:  铝锂合金  电子束焊  超塑性成形

Key words:  aluminum lithium alloy  electron beam weld  superplastic deformation

摘要:

通过高温拉伸试验研究了5A90铝锂合金电子束焊焊板超塑性变形行为. 结果表明，5A90铝锂合金电子束焊焊板具有良好的超塑性变形能力，焊板的峰值流变应力随温度升高及初始应变速率的减小而减小，应变速率小于1×10^-2/s时，焊板峰值流变应力小于32 MPa；焊板的断后伸长率随温度的升高和初始应变速率的增大而先增大再减小，在450℃，5×10^-3/s断后伸长率达到最大为171.1%. 提出变形比例系数K（接头与母材断后伸长率的比值），评价焊板中接头的超塑性变形协调能力，在各变形条件下K值均达到70%以上.

Abstract:

The superplastic deformation behavior of electron beam welded joints of 5A90 aluminum lithium alloys was researched by high temperature tensile test. The results indicated that the electron beam welded joints of 5A90 aluminum lithium alloys present good superplasticity. The peak flow stress decreased while the temperature increased or the initial strain rate decreased, and the flow stress was below 32 MPa while the initial strain rate was below 1×10²/s. The elongation of joints increased first and then decreased with increase of the deformation temperature and initial strain rate, and the maximal elongation of 171.1% was obtained at the optimal parameter 450℃, 5×10³/s. Deformation coefficient K was introduced to characterize the superplasticity of electron beam weld joints. The K values were beyond 70% at all deformation parameters.