等温自由锻温度对7085铝合金组织与性能的影响

通过金相组织观察、扫描电镜分析和室温拉伸力学性能及剥落腐蚀实验,分析探讨等温自由锻温度对7085铝合金显微组织、力学性能和剥落腐蚀的影响.研究结果表明:在370℃和400℃等温自由锻时,合金发生严重再结晶,强度较低,伸长率稍高,剥蚀抗力较差；在420℃锻造时,合金出现大量细小且分布均匀的亚晶粒,抗拉强度、屈服强度、伸长率和剥蚀抗力均较好,分别达到533.2 MPa,495 MPa,13.3％和EA.在450℃锻造时,该合金的晶粒开始长大,强度下降,伸长率稍有升高,剥蚀抗力较差.综合考虑显微组织、强度、塑性和剥落腐蚀等因素,确定420℃为合金等温自由锻最佳锻造温度.

Effects of isothermal free forging temperature on microstructure and properties of 7085 aluminum alloy

The microstructure,mechanical and corrosion property of 7085 aluminum alloy deformed at different isothermal free forging temperatures were analyzed using optical microscope(OM),scanning electron microscope(SEM),mechanical tensile test and exfoliation corrosion.The experimental results show that serious recrystallization occurs at 370 ℃ or 400 ℃,resulting in the strength severely decreases,the elongation increases slightly and exfoliation corrosion gets worse.At 420 ℃,the alloy exhibits small and uniform sub-grain structure,leading to better strength,elongation and exfoliation resistance.The ultimate strength,yield strength and elongation achieve 533.2 MPa,495 MPa and 13.3%,respectively.Exfoliation corrosion grade reaches EA.While the deformation temperature rises 450 ℃,the grains begin to grow up.The strength and exfoliation resistance decrease,but the elongation increases slightly.Considering the factors of microstructure,strength,plastic and exfoliation resistance,420 ℃ is determined to be the best isothermal free forging temperature.