预回复对Al-11.5Zn-3.5Mg-2.3Cu-0.24Zr挤压材固溶-T652组织与性能的影响

Effect of pre-recovery on microstructure and properties of Al-11.5Zn-3.5Mg-2.3Cu-0.24Zr-0.0025Sr aluminum alloy extrusion sub

摘要:

采用硬度与电导率测试、拉伸试验、晶间腐蚀和剥落腐蚀试验、XRD、扫描电镜（SEM）、电子背散射衍射检验(EBSD)等方法，研究了预回复退火对Al-11.5Zn-3.5Mg-2.3Cu-0.24Zr铝合金挤压材固溶-T652处理组织与性能的影响。结果表明：与未经预回复退火相比，预回复退火可有效抑制合金的再结晶，细化晶粒尺寸，降低平均晶界角度，显著提高低角度晶界百分比；预回复退火能够保持同等抗拉强度的情况下，提高该合金的屈服强度和抗腐蚀性能；位错强化和低角度晶界强化是合金的屈服强度提高的主要因素。

Abstract:

Effect of pre-recovery solid solution-T652 treatment and solid solution-T652 treatment on microstructure and properties of Al-11.5Zn-3.5Mg-2.3Cu-0.24Zr-0.0025Sr aluminum alloy extrusion were studied by means of micro-hardness tester and electrical conductivity test, tensile test, intergranular and exfoliation corrosion experiment, scanning electron microscope (SEM) and electron back-scattered diffraction (EBSD). The results show that pre-recovery-annealing treatment can restrain recrystallization effectively, refine the grain size, and reduce the average angle of grain boundaries, increase the percentage of low angle grain boundaries significantly. Pre-annealing can improve the yield strength and the corrosion resistance performance, and maintain the same tensile strength. The increase of the yield strength is attributed to dislocation strengthening and low angel grain boundaries strengthening.