PDF(Pubmed)
Abstract：
To facilitate the manufacturing of the thin-walled components of 2219 aluminum alloy, the quenching-forming-aging (Q-F-A) process has been increasingly utilized. However, natural aging (NA) after quenching significantly affects the cold forming performance of this alloy. In this study, experiments are conducted to investigate the effect of NA time on the cold forming performance of 2219 aluminum alloy. The results indicate that NA can weaken the Portevin-Le Chatelier (PLC) effect, thereby reducing its influence on the cold forming performance of the alloy. The PLC effect becomes indistinct when the aging time reaches 2 years. The yield strength of 2219 aluminum alloy increases monotonically with aging time, while the elongation first increases rapidly and then decreases. After an aging time of 2 years, the yield strength increases by 28.6% from that of newly quenched alloys. The strain hardening index and hardening coefficient indicate that short-term NA (less than 4 days) increases the work hardening rate, while long-term NA reduces it. Microstructural analysis shows that the strengthening effect of NA on 2219 aluminum alloy is mainly due to the growth of G.P. zones and the precipitation of θ″ phases. The NA precipitation behavior can also cause the aggregation of solute atoms and weaken the PLC effect.
摘要：
为了便于2219铝合金薄壁构件的制造，淬火-成形-时效（Q-F-A）工艺已越来越多地使用。然而,淬火后自然时效(NA)显著影响该合金的冷成形性能。在这项研究中,实验研究了NA时间对2219铝合金冷成形性能的影响。结果表明，NA可以削弱Portevin-LeChatelier（PLC）效应，从而降低其对合金冷成形性能的影响。当老化时间达到2年时,PLC效应变得不明显。2219铝合金的屈服强度随时效时间单调增加,而伸长率先迅速增加后下降。经过2年的老化时间，屈服强度比新淬火合金提高了28.6%。应变硬化指数和硬化系数表明，短期NA（小于4天）增加了加工硬化率，而长期NA减少了它。显微组织分析表明，NA对2219铝合金的强化作用主要是由于G.P.区的生长和θ″相的析出。NA沉淀行为也会引起溶质原子的聚集，削弱PLC效应。
