(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；2. 東北輕合金有限責(zé)任公司，哈爾濱 150060)
摘 要: 采用力學(xué)性能、電導(dǎo)率測試、金相和電子顯微分析技術(shù)，研究固溶−時(shí)效處理對Al-Zn-Mg-Sc-Zr鋁合金板材組織與性能的影響。結(jié)果表明：Al-Zn-Mg-Sc-Zr合金板材的最佳熱處理制度為(470 ℃, 1 h，水淬) + (120 ℃, 24 h)；在此條件下，合金的抗拉強(qiáng)度、屈服強(qiáng)度、伸長率、硬度和電導(dǎo)率分別為587 MPa、564 MPa、8.95%、155HB和34.5%(IACS)；固溶過程中，適當(dāng)提高固溶溫度或延長固溶時(shí)間，合金中過剩相逐漸減少，基體過飽和程度增加；時(shí)效過程中，固溶體析出η′ (MgZn2)和η (MgZn2)相，隨時(shí)效時(shí)間延長，晶內(nèi)析出相η′ 粗化，晶界上平衡相也粗化，與此同時(shí)，晶界無析出帶寬化；合金的高強(qiáng)度來源于微量Sc、Zr引起的亞晶強(qiáng)化、Al3(Sc, Zr)粒子和η′ 相的析出強(qiáng)化。
關(guān)鍵字: Al-Zn-Mg合金；固溶；時(shí)效；組織；力學(xué)性能；電導(dǎo)率
Al-Zn-Mg-Sc-Zr alloy sheet
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Northeast Light Alloy Co., Ltd., Harbin 150060, China）
Abstract:The effects of solution and aging treatment on the microstructure and mechanical properties of Al-Zn-Mg-Sc-Zr aluminum alloy sheet were studied by hardness, tensile tests, electric conductivity measurement, optical microscopy and electronic microscopy. The results show that, the appropriate heat-treatment regime of Al-Zn-Mg-Sc-Zr aluminum alloy sheet is solution treated at 470 ℃ for 1 h and water quenching, and then aged at 120 ℃ for 24 h. Under this condition, the mechanical properties of σb, σ0.2 and δ5, the hardness and conductivity reach 587MPa, 564 MPa, 8.95%, 155HB and 34.5%(IACS), respectively. As the increases of the solution temperature and time, the major remainders disappear gradually and the strength of the alloy is improved. During the aging process, η′ and η phases precipitate from the solid solution, with the increase of the aging time, the η′ and η phases are both coarsened, and so as the precipitate free zone(PFZ). The high strength is mainly due to the subgrain strengthening caused by the addition of Sc and Zr, the Al3(Sc, Zr) particles and the precipitation of η′ phase.
Key words: Al-Zn-Mg alloy; solid solution; aging; microstructure; mechanical property; electric conductivity
