Sn微合金化和时效温度对Al‑Mg‑Si合金微观结构和力学性能的影响

Effect of Sn microalloying and ageing temperature on microstructure and mechanical properties of Al‑Mg‑Si alloy

通过硬度测试、DSC热分析、扫描电子显微镜和透射电子显微镜系统研究了Sn微合金化和时效温度对Si过量Al⁃Mg⁃Si合金微观结构和力学性能的影响。Sn元素的添加可以有效地抑制自然时效期间团簇(1)(Mg⁃Si共同团簇)的形成,降低合金自然时效的硬度,以及在随后人工时效过程中促进弥散相的析出强化作用。Al⁃Mg⁃Si(⁃Sn)合金在200℃人工时效下较170℃有更佳的析出强化效果。随着人工时效温度的升高,β"相的析出速率增加并伴有粗化效果。此外,促进Al⁃Mg⁃Si(⁃Sn)合金析出强化的最佳人工时效温度为200℃。Si过量Al⁃Mg⁃Si合金通过添加Sn元素,并在自然时效处理后进行高温人工时效,可以改善其力学性能,从而使峰值硬度达到128.6 HV。最佳热处理方法为:自然时效(2周)+人工时效(200℃×30 min)。本论文的研究对开发使用新型铝合金的汽车具有潜在的意义。

The effect of Sn addition and aging temperature on the microstructure and mechanical prop⁃erties of Si-excess Al-Mg-Si alloys is examined through a series of tests.The incorporation of Sn ele⁃ments greatly inhibits the formation of Cluster(1)(Mg-Si co-cluster)and reduces the adverse effects of the natural aging(NA)while simultaneously boosting precipitation strengthening during subsequent artificial aging(AA).Compared with the AA at 170℃,Al-Mg-Si(-Sn)alloys exhibit superior pre⁃cipitation hardening at 200℃AA.As the temperature of AA increases,both the precipitation rate and coarsening of theβ"phase are accelerated.Furthermore,200℃is found to be the most effective tem⁃perature for enhancing precipitation in Sn-added alloy through AA.The mechanical properties of Siexcess Al-Mg-Si alloys can be improved by adding Sn and subjecting it to high-temperature AA after NA,resulting in a peak hardness of 128.6 HV.These findings have potential implications for develop⁃ing automobiles using new aluminum alloys.