Polycrystalline behavior analysis of extruded magnesium alloy AZ31

Uniaxial tensile and compressive tests were performed at room temperature on extruded AZ31 Mg alloy specimens and distinct tensile-compressive anisotropy was detected. Deformed specimens were examined and the results indicate that the generation of {10 $\bar 1$ 2}〈10 $\bar 1$ 1〉 twin is responsible for the mechanical anisotropy. A rate independent crystal plasticity model, which accounts for both slip and twinning, was developed for polycrystalline hexagonal close packed (HCP) materials. Model predictions for the stress-strain curves and texture evolution were in reasonable agreement with the experimental results. Specifically, the model captured the three stages of strain hardening for uniaxial-compression. By comparing stress-strain curves and texture evolution between model predictions and experimental measures, information about the dominant slip and twinning systems active at room temperature was deduced.     

基于图像识别的高压铸造铝合金缺陷特征分析及缺陷对性能影响的研究

利用温室拉伸、扫描电镜，以及基于深度学习和阈值分割法开发的缺陷自动识别和统计程序，研究了缺陷对高压压铸铝合金机械性能的影响规律。结果表明，高压压铸铝合金铸件不同位置的力学性能具有波动性；对比图像识别程序和人工统计断口缺陷面积结果，验证了图像识别程序的精度；断口缺陷面积和力学性能关系表明，孔隙率和最大缺陷尺寸与延伸率具有相关性，当孔隙率或最大缺陷尺寸上升时，高压铸造铝合金的延伸率呈下降趋势。