预变形方式对T76时效态7475铝合金组织及性能的影响

Effects of Pre-deformation Mode on Microstructure and Property of T76 Aged 7475 Aluminum Alloy

通过透射电镜组织观察、拉伸试验、剥落腐蚀试验以及极化曲线试验,研究了拉伸与轧制预变形方式对7475铝合金组织、强度与抗腐蚀性能的影响。结果表明,预变形引入大量位错,且在125℃/3 h时效后仍大部分残留;轧制预变形表面位错多于中心位错;拉伸预变形与轧制预变形都导致T76过时效态7475铝合金中η'相减少、η相增多、晶内析出相尺寸增大、晶界析出相间距减小、合金强度与抗腐蚀性能降低;当变形量一致时,轧制预变形比拉伸预变形处理的合金强度高,但抗腐蚀性能低。

Effects of pre-deformation mode of stretching and rolling on the microstructure and properties of T76 aged7475 aluminum alloy were studied by transmission electron microscope analyses,tensile tests,exfoliation corrosion tests and polarization tests.Results showed that the pre-deformation brought a large number of dislocations,most of which still remained after aging at 125 ℃ for 3 hrs.The density of dislocations on the surface of the pre-rolled sample was higher than that at the center.For the T76 aged 7475 aluminum alloy,both pre-rolling and pre-stretching deformation decreased the proportion of η’ precipitates,the distance between grain-boundary precipitates,the strength and corrosion resistance but increased the proportion of η precipitates and size of intracrystalline precipitates.With the same pre-deformation percent,the pre-rolled sample showed higher strength and lower corrosion resistance,in comparison with the pre-stretched sample.