Mrówka-Nowotnik Grażyna, Boczkal Grzegorz, Nowotnik Andrzej
Department of Material Science, Rzeszow University of Technology, Al. Powstańców Warszawy 12, 35-959 Rzeszow, Poland.
Faculty of Non-Ferrous Metals, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow, Poland.
Materials (Basel). 2024 Jul 12;17(14):3447. doi: 10.3390/ma17143447.
The growing use of aluminum and its compounds has increased the volume of aluminum waste. To mitigate environmental impacts and cut down on manufacturing expenses, extensive investigations have recently been undertaken to recycle aluminum compounds. This paper outlines the outcomes of a study on fabricating standard EN AW-2007 alloy using industrial and secondary scrap through continuous casting. The resultant recycled bars were analyzed for their chemical makeup and examined for microstructural features in both the cast and T4 states, undergoing mechanical property evaluations. The study identified several phases in the cast form through LM, SEM + EDS, and XRD techniques: AlCuFe, θ-AlCu, β-MgSi, Q-AlCuMgSi, and α-Al(FeMn) (SiCu) along with Pb particles. Most primary intermetallic precipitates such as θ-AlCu, β-MgSi, and Q-AlCuMgSi dissolved into the α-Al solid solution during the solution heat treatment. In the subsequent natural aging process, the θ-AlCu phase predominantly emerged as a finely dispersed hardening phase. The peak hardness achieved in the EN AW-2007 alloy was 124.8 HB, following a solution heat treatment at 500 °C and aging at 25 °C for 80 h. The static tensile test assessed the mechanical and ductility properties of the EN AW-2007 alloy in both the cast and T4 heat-treated states. Superior strength parameters were achieved after solution heat treatment at 500 °C for 6 h, followed by water quenching and natural aging at 25 °C/9 h, with a tensile strength of 435.0 MPa, a yield strength of 240.5 MPa, and an appreciable elongation of 18.1% at break. The findings demonstrate the feasibility of producing defect-free EN AW-2007 alloy ingots with excellent mechanical properties from recycled scrap using the continuous casting technique.
铝及其化合物的使用日益增加，导致铝废料的数量也在增多。为了减轻环境影响并降低制造成本，最近人们开展了大量研究以回收铝化合物。本文概述了一项关于通过连续铸造利用工业废料和二次废料制造标准EN AW - 2007合金的研究成果。对所得的再生棒材进行了化学成分分析，并对铸态和T4态的微观结构特征进行了检查，同时进行了力学性能评估。通过金相显微镜（LM）、扫描电子显微镜 + 能谱仪（SEM + EDS）和X射线衍射仪（XRD）技术，研究确定了铸态中的几个相：AlCuFe、θ - AlCu、β - MgSi、Q - AlCuMgSi和α - Al(FeMn)(SiCu)以及铅颗粒。在固溶热处理过程中，大多数初生金属间化合物析出相，如θ - AlCu、β - MgSi和Q - AlCuMgSi，溶解到α - Al固溶体中。在随后的自然时效过程中，θ - AlCu相主要以细小弥散的强化相形式出现。在500 °C进行固溶热处理并在25 °C时效80小时后，EN AW - 2007合金达到的峰值硬度为124.8 HB。静态拉伸试验评估了EN AW - 2007合金在铸态和T4热处理态的力学性能和延展性。在500 °C固溶热处理6小时，随后水淬并在25 °C自然时效9小时后，获得了优异的强度参数，抗拉强度为435.0 MPa，屈服强度为240.5 MPa，断裂伸长率为18.1%。研究结果表明，使用连续铸造技术从回收废料中生产出具有优异力学性能且无缺陷的EN AW - 2007合金铸锭是可行的。
