(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
3. 常州億和航宇材料科技有限公司，常州 213017)
摘 要: 采用顯微硬度測(cè)試、室溫拉伸試驗(yàn)，電導(dǎo)率測(cè)試和透射電鏡等方法，對(duì)不同室溫停放時(shí)間經(jīng)過(guò)人工時(shí)效后的Al-Zn-Mg合金的力學(xué)性能、電導(dǎo)率和透射微觀組織進(jìn)行研究。結(jié)果表明：Al-Zn-Mg鋁合金不經(jīng)過(guò)室溫停放時(shí)性能最優(yōu)，強(qiáng)度、伸長(zhǎng)率和硬度可以達(dá)到502.71 MPa、10.20%和173.20 HV；不同的室溫停放時(shí)間Al-Zn-Mg合金的晶內(nèi)析出相尺寸、數(shù)量以及晶界析出形貌和無(wú)沉淀析出帶(PFZ)的寬度不同，室溫停放3~6 h合金的綜合性能優(yōu)良，強(qiáng)度均能達(dá)到450 MPa以上，晶內(nèi)析出相為亞穩(wěn)相η′和平衡相η，晶界分布著斷續(xù)的平衡相，PFZ寬度約為40~50 nm；室溫停放的時(shí)間會(huì)影響后續(xù)人工時(shí)效GP區(qū)的形核。
關(guān)鍵字: Al-Zn-Mg鋁合金；停放時(shí)間；析出相；力學(xué)性能
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China;
3. Changzhou Yihe Hangyu Material Technology Co., Ltd., Changzhou 213017, China）
Abstract:The mechanical properties, electrical conductivity and transmission microstructure of Al-Zn-Mg alloy after artificial aging for different parking time were investigated using micro-hardness test, room temperature tensile test, conductivity test and transmission electron microscope. The results show that Al-Zn-Mg aluminum alloy has the best performance without being parked at room temperature, and its strength, elongation and hardness can reach 502.71 MPa, 10.20% and 173.20 HV, respectively. The intragranular Al-Zn-Mg alloy, size and number of precipites, precipitates morphology of grain boundaries and width of precipitation free zone (PFZ) are different at different room temperature parking time. The comprehensive performance is excellent when parked at room temperature for 3-6 h, and the strength can reach more than 450 MPa. The intragranular precipitates are metastable phase η′ and equilibrium phase η. The grain boundaries are distributed with intermittent equilibrium phases, and the width of PFZ is about 40-50 nm. The parking time at room temperature will affect the nucleation of GP zone with subsequent artificial aging.
Key words: Al-Zn-Mg aluminum alloy; parking time; precipitates; mechanical properties
