Cu元素含量对Al-Zn-Mg-Cu系合金析出行为的影响

Effect of Cu Content on Precipitation Behavior of Al-Zn-Mg-Cu Aluminum Alloy

采用热力学模拟手段研究了Al-Zn-Mg-Cu系合金中不同Cu含量对析出相GP区及η′相的析出规律。结果表明,GP区及η′相中含部分Cu元素;在120℃和160℃时效时,随Cu元素含量从1.9%(质量分数,下同)增加到2.5%,GP区含量有所降低分别从2.65%和1.11%降低到2.60%和1.02%,而η′相含量有所增加,分别从6.71%和6.52%增加到7.25%和7.07%。当强化相η′相含量达到6.5%时所用时间随Cu含量的增加而减少,当Cu含量从1.9%增加到2.5%时,120℃和160℃所用时间分别从23 h和5 h缩短到16 h和2.8 h。不同Cu含量下GP区和η′相的鼻尖温度区间分别为150℃和330℃,基本保持不变,临界冷却速率基本保持在16℃/s,说明Cu含量对合金的淬火敏感性影响较小。

The effects of Cu content on precipitation behavior of GP area andη′phase of Al-Zn-Mg-Cu aluminum alloy was investigated by using the aluminum alloy module in thermodynamic simulation software in detail.The results show that the content of some Cu element was in GP area andη′phase.Under aging temperature of 120℃and 160℃,with the increase of Cu content from 1.9%to 2.5%,the content of GP area decreased from 2.65%and 1.11%to 2.60%and 1.02%respectively.While the content ofη′phase decreased from 6.71%and 6.52%to 7.25%and 7.07%respectively.The used time ofη′phase content reaching 6.5wt%decreased with the increase of Cu content.The time from 23 h and 5 h droped down to 16 h and 2.8 h with the increase of Cu content at the aging temperature 120℃ and 160℃,respectively.The nose temperature kept at 150℃ of GP area and 330℃ of η′phase with the increasing of Cu content,as well as the critical cooling ratio kept at 16℃/s.In other words,the content of Cu have a little effect on quenching sensitivity.