Mrówka-Nowotnik Grażyna, Boczkal Grzegorz, Nabel Damian
Department of Material Science, Rzeszow University of Technology, Al. Powstancow Warszawy 12, 35-959 Rzeszow, Poland.
Faculty of Non-Ferrous Metals, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cra-cow, Poland.
Materials (Basel). 2025 Mar 11;18(6):1235. doi: 10.3390/ma18061235.
This study investigated the effect of the recycling process on the microstructure, hardness, and precipitation kinetics of strengthening phases in the 2017A aluminum alloy. Light microscopy (LM) and X-ray diffraction (XRD) analyses revealed that the as-cast microstructure of the recycled 2017A alloy contained intermetallic phases, including θ-AlCu, β-MgSi, AlCuFe, Q-AlCuMgSi, and α-Al(FeMn)(SiCu), and was comparable to that of the primary alloy, confirming its potential for high-performance applications. During solution heat treatment, most of the primary intermetallic precipitates, such as AlCu, MgSi, and Q-AlCuMgSi, dissolved into the solid Al matrix. DSC analysis of the solution-treated alloy established the precipitation sequence as follows: α-ss → GP/GPB zones → θ″ → θ'/Q' → θ-AlCu/Q-AlCuMgSi. The combined results from XRD, LM, TEM, and DSC confirmed that both θ and Q phases contributed to strengthening, with θ″ and θ' phases playing a dominant role. Brinell hardness measurements during natural and artificial aging revealed that hardness increased with aging time, reaching a maximum value of 150.5 HB after ~22 h of artificial aging at 175 °C. The precipitation kinetics of the recycled 2017A alloy was studied via DSC measurements over a temperature range of ~25 to 550 °C, at heating rates of 5, 10, 15, 20, and 25 °C/min. The peak temperatures of clusters, GP zones, and hardening phases (θ', θ″, θ, and Q) were analyzed to calculate the activation energy using mathematical models (Kissinger, Ozawa, and Boswell). The obtained values of activation energies of discontinuous precipitation were comparable across methods, with values for the θ″ phase of 89.94 kJ·mol (Kissinger), 98.7 kJ·mol (Ozawa), and 94.33 kJ·mol (Boswell), while for the θ' phase, they were 72.5 kJ·mol (Kissinger), 81.9 kJ·mol (Ozawa), and 77.2 kJ·mol (Boswell). These findings highlighted the feasibility of using recycled 2017A aluminum alloy for structural applications requiring high strength and durability.
本研究调查了回收工艺对2017A铝合金微观结构、硬度及强化相析出动力学的影响。光学显微镜（LM）和X射线衍射（XRD）分析表明，回收的2017A合金铸态微观结构包含金属间相，包括θ-AlCu、β-MgSi、AlCuFe、Q-AlCuMgSi和α-Al(FeMn)(SiCu)，与原生合金的微观结构相当，证实了其在高性能应用方面的潜力。在固溶热处理过程中，大多数原生金属间析出物，如AlCu、MgSi和Q-AlCuMgSi，溶解到固态Al基体中。对固溶处理后的合金进行DSC分析确定析出顺序如下：α-ss→GP/GPB区→θ″→θ'/Q'→θ-AlCu/Q-AlCuMgSi。XRD、LM、TEM和DSC的综合结果证实，θ相和Q相均有助于强化，其中θ″相和θ'相起主导作用。自然时效和人工时效过程中的布氏硬度测量表明，硬度随时效时间增加，在175℃下人工时效约22小时后达到最大值150.5 HB。通过在约25至550℃温度范围内、以5、10、15、20和25℃/分钟的加热速率进行DSC测量，研究了回收的2017A合金的析出动力学。分析了团簇、GP区和强化相（θ'、θ″、θ和Q）的峰值温度，以使用数学模型（基辛格、小泽和博斯韦尔）计算活化能。通过不同方法获得的不连续析出活化能值相当，θ″相的值分别为89.94 kJ·mol（基辛格）、98.7 kJ·mol（小泽）和94.33 kJ·mol（博斯韦尔），而θ'相的值分别为72.5 kJ·mol（基辛格）、81.9 kJ·mol（小泽）和77. kJ·mol（博斯韦尔）。这些发现突出了将回收的2017A铝合金用于需要高强度和耐久性的结构应用的可行性。
