(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 通過電導(dǎo)率、常溫力學(xué)性能測試和透射電鏡研究了時效對7055鋁合金淬火敏感效應(yīng)的影響。結(jié)果表明：合金固溶后慢速淬火時，晶粒內(nèi)部和晶界上析出大量粗大的η平衡相，基體中的溶質(zhì)過飽和度及空位濃度大大降低，不利于時效時強化相的均勻彌散析出，導(dǎo)致合金的力學(xué)性能下降；雙級時效對快速淬火合金的力學(xué)性能影響不大，但提高了慢速淬火合金的力學(xué)性能，因而一定程度減少了合金的淬火敏感效應(yīng)；這是因為相對單級時效而言雙級時效可使慢速淬火合金中得到更多強化相，分布也更均勻彌散，從而減小空位濃度降低帶來的不利影響；在本研究中，100 ℃, 24 h+121 ℃, 24 h是最佳的雙級時效制度。
關(guān)鍵字: 7055鋁合金；時效；淬火敏感效應(yīng)
of 7055 aluminum alloy
（School of Materials Science and Engineering, Central South University,Changsha 410083, China）
Abstract:The influence of aging on the quench sensitivity effect of 7055 aluminum alloy was investigated by electrical conductivity test, ambient temperature tensile properties test and transmission electron microscopy. The results show that many coarse equilibrium η particles precipitate in grains and on grain boundaries in the alloy during slow quenching after solution treatment, which reduces the solutes available for aging hardening. Meanwhile, the vacancy concentration is also decreased, which is unfavorable for homogeneous nucleation. Thus, the mechanical properties of slow-quenched alloy after aging are decreased. Duplex aging has slight influence on the mechanical properties of the rapid-quenched alloy, but increases that of the slow-quenched one, thus eliminates the quench sensitivity effect to some extent. This is because that duplex aging results in more amounts of dispersing and homogeneously distributing hardening precipitates, and reduces the negative effect due to lower vacancy concentration. The optimal duplex aging in this investigation is 100 ℃, 24 h+121 ℃, 24 h.
Key words: 7055 aluminum alloy; aging; quench sensitivity effect
