形变热处理对2A12铝合金微观组织、织构及性能的影响

Effect of Deformation Annealing on Microstructure, Texture and Properties of 2A12 Aluminum Alloy

摘要:

利用扫描电镜显微观察（含能谱分析）和电子背散射衍射技术（Electron Backscatter Diffraction， EBSD）等分析方法研究了不同形变热处理制度对2A12铝合金板材的微观组织、织构及性能的影响。结果表明：2A12铝合金经形变热处理后，晶粒沿轧制方向拉长，晶粒尺寸减小。随着形变热处理反复次数的增加，亚晶界比例降低，2°?15°的小角度晶界比例提高，大角度晶界比例先增后减，此时的退火过程由回复多边化主导转变为再结晶主导，再结晶程度提高。单步形变热处理样品因形变量较小，大小晶界和亚晶界比例较为接近。与退火制度相同的小变形样品相比，大形变热处理样品亚晶减少，大角度和小角度晶界增加，再结晶程度提高。形变量较大时，将存在Brass→R-Cu和m-Brass→Goss→R-Goss→Cube、T和P_0°→Near rotated Cube和｛102｝<201>的织构演变路径。单步小变形退火时，路径将改变为：R-Cu和m-Brass→Goss→R-Cube。随着变形量的增加，2A12铝合金的强度和硬度增加，韧性和塑性降低。

Abstract:

The effects of different deformation annealing processes on the microstructure, texture, and properties of 2A12 aluminum alloy were studied by scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS) and electron backscatter diffraction (EBSD). Results demonstrate that after deformation annealing treatment, the 2A12 aluminum alloy grains become longer along the rolling path and smaller in size. The proportion of subgrain boundaries decreases, the proportion of low angle grain boundaries (LAGB) at 2°?15° increases, and the proportion of high angle grain boundaries (HAGB, >15°) first increases and then declines as the deformation annealing treatment cycles increase. The degree of recrystallization rises at this point as the annealing process switches from recovery multi-lateralization to recrystallization. After single-step deformation annealing, the two samples have a similar microstructure and proportion of HAGB and LAGB in total due to the small deformation and less deformation stored energy. Compared to the sample that underwent mild deformation with the same annealing process, the large deformation sample has a lower proportion of subgrain boundaries in total and a higher proportion of LAGBs and HAGBs, and the degree of recrystallization increases. There will be texture evolution pathways of Brass→R-Cu and m-Brass→Goss→R-Goss→Cube, T and P_0°→Near rotated Cube and {102}<201> when the deformation is significant. R-Cu and m-Brass→Goss→R-Cube will become the new route during single-step small deformation annealing. The toughness and plasticity of the 2A12 aluminum alloy diminish while the strength and hardness rise with higher deformation.