本文關(guān)鍵詞：稀土變質(zhì)對Al-Fe系合金組織及力學性能的影響　出處：《內(nèi)蒙古工業(yè)大學》2015年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 鋁合金 稀土變質(zhì) 富鐵相 退火 軋制

【摘要】：Al-Fe金屬間化合物具有優(yōu)良的耐熱、耐磨和抗氧化性能,但對于Al-Fe系合金,由于Al-Fe金屬間化合物其形貌呈粗大的針狀或片狀結(jié)構(gòu),嚴重割裂基體和影響合金的力學性能,所以本文主要研究利用富Ce混合稀土改善和提高Al-1wt%Fe、8011A及高鐵含量鋁鐵合金的組織和力學性能。首先添加不同含量的富Ce混合稀土對鋁鐵合金進行變質(zhì)處理,其次對合金進行均勻化退火,最后通過冷軋塑性變形工藝細化合金組織、改善富鐵相有害形貌,從而有效地提高鋁鐵合金的力學性能。利用光學顯微鏡,XRD,SEM及EDS等方法分析金相顯微組織、物相組成、元素含量及分布。在對Al-1wt%Fe合金的研究中表明,當富Ce混合稀土的加入量為0.3wt%時變質(zhì)效果最佳,晶粒明顯細化,同時Al-Fe相也得到改善,由最初的片狀或針狀轉(zhuǎn)變?yōu)槎虠U狀或橢球狀;經(jīng)480℃、24h均勻化退火后晶界處針狀或桿狀Al-Fe相有熔斷現(xiàn)象;經(jīng)冷軋變形后發(fā)現(xiàn)晶界處Al-Fe破碎,晶粒再次細化,且隨著變形量的增加,Al-Fe相的破碎更加充分,分布也更加均勻。試驗證明鑄態(tài)時未添加稀土時合金抗拉強度為84.03MPa,稀土量為0.3wt%時抗拉強度為86.42MPa;經(jīng)80%冷軋變形后,含稀土為0.3wt%的合金有最大的抗拉強度值為163.2MPa。在對8011A鋁合金的研究表明,其變質(zhì)效果最佳的富Ce稀土加入量仍然為0.3wt%,由于其他合金元素的加入,其形貌由之前的桿狀或針狀更多的轉(zhuǎn)變?yōu)槎噙呅纹瑺�、短桿狀或球狀;經(jīng)450℃、24h退火后晶界處富鐵亦有熔斷的現(xiàn)象,針狀的富鐵相斷為桿狀;冷軋變后,晶粒的細化程度進一步提高,在擠壓力的作用下晶界處富鐵相充分破碎,均勻的彌撒的分布于基體中。實驗表明鑄態(tài)時未添加稀土變質(zhì)的合金抗拉強度為116.32MPa,稀土量為0.3wt%時抗拉強度為117.46MPa;當經(jīng)過80%冷軋變形后,含稀土為0.3wt%的合金有最大的抗拉強度值為202.65MPa。在對高鐵含量鋁鐵合金的研究表明,隨著鐵含量的增加,合金基體中Al-Fe相從短桿狀變?yōu)殚L針狀或有棱角片狀,當Fe含量為6wt%時,變?yōu)榇执蟮尼槧罨蜓┗�。當富Ce稀土的加入量為0.7wt%和0.9wt%時變質(zhì)效果最好,合金基體中雪花狀、粗板狀和大針狀的富鐵相有明顯的減少,且部分轉(zhuǎn)變?yōu)榧氠槧�、細板狀、短桿狀和橢球狀,退火后Al-Fe相有熔斷的現(xiàn)象即針狀的Al-Fe斷裂為桿狀,同時基體中球狀的Al-Fe相數(shù)量明顯增加,說明熱處理對Al-Fe有一定的球化效果。
[Abstract]:Al-Fe intermetallic compounds have excellent heat resistance, wear resistance and oxidation resistance, but for Al-Fe alloys, the morphology of Al-Fe intermetallics is coarse needle-like or flake. The mechanical properties of the alloy were seriously severed and the mechanical properties of the alloy were affected. Therefore, the use of ce rich mixed rare earths to improve and improve the Al-1wt was studied in this paper. The microstructure and mechanical properties of Al-Fe alloy with 8011A and ferric iron content. Firstly, the Al-Fe alloy was modified by adding different content of mixed rare earth with rich ce, and then homogenized annealing was carried out. Finally, the microstructure of the alloy was refined by the cold rolling plastic deformation process, and the harmful morphology of the Fe-rich phase was improved, thus the mechanical properties of the Al-Fe alloy were effectively improved. The microstructure, phase composition, element content and distribution of Al-1wt alloy were analyzed by SEM and EDS. When the amount of ce rich mixed rare earth is 0.3 wt%, the modification effect is the best, the grain size is obviously refined, and the Al-Fe phase is improved, from the initial flake or needle to the short rod or ellipsoid. After annealing at 480 鈩，

本文編號：1403154