Microstructural and Mechanical Behavior in the Al₂₀₂₄ Alloy Modified With Addition of CeO₂

Abstract

The 2xxx series aluminium alloys are important advanced functional materials due to their high yield strength, good fracture toughness and excellent fatigue properties [1]. Due to the extremely important role that the 2xxx series aluminum alloys play in the aviation industry, much attention has been devoted to understanding their structures and properties [1][2]. Particularly, comprehensive investigations have been made to elucidate the morphological dependence of the precipitates on material composition, thermal treatment history, and impurity elements to optimize the materials performance for designed applications [1][2].By another hand, in the last decades, the use of metallic matrix composites of two or more different metals, intermatallic compounds or second phases has been researched widely. They are produced by controlling the properties of the constituent phases, their relative amount, dispersed phase geometry including particle size, shape and orientation in the matrix to achieve optimum combination of microstructural and mechanical properties [3, 4]. Reinforcing particle such as SiC, Al 2 O 3 , and MgO, have emerged as a potential alternative for conventional aluminum-base composites because of their high mechanical properties. Additionally, because the effects on microstructure, mechanical properties, electrical conductivity and corrosion resistance the use of rare earth, especially La, Ce, Nd, Y and Sc have called attention, recently. Thus, the present work evaluates the effect of CeO 2 nanoparticles on the microstructure, precipitation sequence and hardening mechanisms of the Al 2024 alloy.A compound of Al-16.66% by weight of CeO 2 (CMAlCeO 2 ) was prepared by mechanical milling (Fig.1). Subsequently, the CMAlCeO 2 was added in proportions of 0.1, 0.5,3 and 5 wt. % of CeO 2 to the Al 2024 alloy by conventional casting. Finally, the material obtained was extruded and aged. The characterization of CMAlCeO 2 suggests a reaction of the chemical reduction of CeO 2 and the formation of a layer of Al 2 O 3 that covers the elemental Ce during the process (Fig.2). On the other hand, the hardness tests indicate that the lower content of CMAlCeO 2 (0.1, 0.5% weight of CeO 2 ) obtained hardness superior to the commercial alloy Al 2024 . In addition, the preparation of the CMAlCeO 2 composite material by powder metallurgy is an alternate route for homogeneously dispersing CeO 2 nanoparticles in an aluminum matrix. However, long sintering times are not recommended since this favors the formation of elongated Ce rich phases.

Al-MgO Kompozitlerin Toz Metalurjisi Yöntemiyle Üretilmesi ve Kompozitlerin Özelliklerine Sinterleme Sıcaklığının Etkisi

“…MgO (magnezyum oksit), iyi ıslatılabilirlik, yüksek sertlik, korozyona karşı yüksek direnç, yüksek basma mukavemeti ve geri dönüştürülebilir özelliklerine sahip, doğada bol miktarda bulunan hafiftir bir bileşiktir ve çok çeşitli uygulamalarda yaygın bir şekilde kullanılmaktadır [30,31]. MgO gibi güçlendirici parçacıklar, yüksek mekanik özellikleri nedeniyle geleneksel alüminyum esaslı kompozitler için potansiyel bir alternatif olarak kullanılmaktadır [32]. Bu çalışmada, MgO nano partikül ilave edilmiş alüminyum matrisli kompozitler toz metalurjisi yöntemiyle üretilmiş ve kompozitlerin mikroyapı ve mekanik özelliklerine sinterleme sıcaklığının etkisi araştırılmıştır.…”