新型热机械处理对Al-Zn-Mg-Cu合金显微组织与性能的影响

Effect of new thermomechanical treatment on microstructure and properties of Al-Zn-Mg-Cu aluminum alloy

通过拉伸实验、慢应变速率实验、剥落腐蚀实验、扫描电镜和透射电镜观察,研究新型热机械处理对Al-Zn-Mg-Cu合金显微组织及性能的影响。结果表明:冷变形最终热机械处理能够使合金在塑性不显著降低的情况下,提高合金的强度,温变形最终热机械处理能有效弥补常规最终热机械处理后伸长率较低的缺陷,同时能有效改善合金的抗剥落腐蚀性能;回归后冷变形可提高合金强度,但降低了合金的伸长率;回归后温变形处理能使合金获得良好的综合性能,如力学性能、抗应力腐蚀性和抗剥蚀性能。新型热机械处理改善合金性能的机理是合金晶粒形态、位错、初生相以及析出相等显微组织结构的协同作用。

The effects of new thermomechanical treatment (TMT) on the microstructure and properties of Al-Zn-Mg-Cu alloy were studied by tensile test, slow strain rate tensile test (SSRT),exfoliation corrosion test (EXCO), scanning electron microscopy and transmission electron microscopy. The results indicate that the cold deformation final thermomechanical treatment (FTMTc) process can significantly increase the strength of the alloy without obvious plasticty loss,and warm deformation find thermomechanical treatment (FTMTw) at 200℃can simultaneously improve the elongation and EXCO resistance. Cold rolling after regression (RRCA) can obtain high strength but low elongation, while warm rolling after regression (RRWA) can obtain good mechanical properties and a good combination of stress corrosion resistance (SCR) and exfoliation corrosion resistance. The mechanism of the new TMT process that improves the properties of the alloy is the synergistic effect of composite structures, such as grain structure, dislocations, as well as the size and distribution of primary phase and precipitate phase.