Effects of Melt Thermal-Rate Treatment on Fe-Containing Phases in Hypereutectic Al-Si Alloy

Wang, Qinglei; Geng, Haoran; Zhang, Shuo; Jiang, Haiyue; Zuo, Min

doi:10.1007/s11661-013-2081-4

Cited by 20 publications

(7 citation statements)

References 18 publications

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“…Dependendo da capacidade de absorção de calor pelo molde o processo irá se desenvolver com influência direta nas taxas de resfriamento da peça. A variação nas condições de solidificação afeta a termodinâmica envolvida no processo, e consequentemente a transferência de calor, fazendo com que imponham condições que determinarão a morfologia de crescimento e a velocidade de solidificação [17,18]. Além disso, o aumento do superaquecimento provoca um refino de grãos das fases primárias em ligas hipoeutéticas [19].…”

Section: Discussionunclassified

Influência das variáveis de solidificação na microestrutura e microdureza de ligas Al-Cu utilizando planejamento fatorial complete

Silva

Castro

2022

Matéria (Rio J.)

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RESUMO Neste trabalho utilizou-se uma liga hipereutética Al-40wt%Cu para verificar a influência das variáveis de entrada taxa de resfriamento (°C/min) e superaquecimento (°C), na variável de saída microdureza (HV). As amostras foram vazadas em cadinhos de cerâmica e de cobre e um termopar acoplado à um sistema de aquisição de dados mediu as taxas de resfriamento que foram 20°C/min e 24°C/min, respectivamente. Avaliou-se a influência dessas taxas de resfriamento e do superaquecimento de 100°C e 200°C acima da temperatura de fusão da liga na microdureza. As medições de dureza Vickers foram realizadas na seção transversal da amostra com área de 0,8 cm2. As amostras foram caracterizadas microscopicamente para avaliar a formação microestrutural. O potencial das variáveis envolvidas no estudo foi avaliado por um planejamento fatorial completo 22. Os resultados do planejamento fatorial indicaram que as amostras solidificadas usando o superaquecimento de 200°C acima da temperatura de fusão e resfriadas a uma taxa de 24°C/min obteve maiores valores de microdureza. As ligas superaquecidas em maiores temperaturas apresentaram microestruturas mais refinadas com grãos alongados, direções de crescimento desordenadas e espaçamento dendrítico curto, provocando uma transição na microestrutura colunar para equiaxial.

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Section: Discussionunclassified

Influência das variáveis de solidificação na microestrutura e microdureza de ligas Al-Cu utilizando planejamento fatorial complete

Silva

Castro

2022

Matéria (Rio J.)

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“…A transition from dendritic grains to globular grains was also noted during thermal-rate processing of the aluminum alloy Al-9Si-0.5Mg [32]. It was observed that superheat treatment helped to reduce the harmful effects of iron impurities in Al-Si alloys due to its transfer to a more favorable morphology [27]. Certain successes were achieved in the modification of magnesium-based alloys by melt overheating [33].…”

Section: Introductionmentioning

confidence: 90%

“…The high-temperature type of short-range order (SRO) structure of the melt can be fixed by rapid cooling of the melt before pouring [26], since the rate of structural transformations in the liquid phase is rather low, despite the relatively high rates of diffusion processes. Due to the low rate of structural changes in the liquid phase, rapid cooling of the melt can largely suppress the transformation of clusters and other various atomic groups [27,28]. Due to this, by the use of overheat treatment with fast melt cooling, it is possible to fix to a certain extent the high-temperature type of structure of the liquid phase at the time of pouring the melt into the mold.…”

Section: Introductionmentioning

confidence: 99%

Effect of Melt Overheating on Structure and Mechanical Properties of Al-Mg-Si Cast Alloy

Деев

Прусов

et al. 2021

Metals

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The paper discusses the complex effect of melt overheating with subsequent fast cooling down to the pouring temperature on the crystallization process, microstructure and mechanical properties of Al-Mg-Si aluminum alloy. The results obtained facilitated the establishment of rational modes of melt overheating, leading to a significant change in the dispersion and morphology of structural components. In particular, with an increase in the melt overheating temperature to 900 °C with holding and subsequent rapid cooling to the casting temperature, a decrease in the average size of dendritic cells of the aluminum solid solution from 39 μm to 13 μm was observed. We also noticed the refinement of eutectic inclusions of the Mg2Si phase with compact morphology. An increased level of mechanical properties was noted; the maximum values of tensile strength and elongation reached 228 MPa and 5.24%, respectively, which exceeded the initial values by 22.5% and 52.3%, correspondingly. The microhardness of the aluminum solid solution sequentially increased from 38.21 to 56.5 HV with an increase in the temperature during melt overheating. According to the EDS linear scanning, an increase in the superheat temperature of the melt is accompanied by an increase in the degree of saturation of the solid solution with magnesium.

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“…다양하게 연구되고 있는데, 화학적 개량화제의 첨가 [11], 급 속 응고 [12], 과열처리 [13] 및 초음파용탕처리 [2,14,15] 등 에 대한 연구가 보고되고 있다. 이중에서 초음파용탕처리 는 합금의 미세조직을 미세화시킬 뿐만 아니라 주조품의 품질을 향상 시킬 수 있기 때문에 효과적인 방법 중 하나 로 간주되며 [16][17][18][19], 냉각속도가 클수록 더 좋은 효과를 보 이는 것으로 보고되어 있다 [2,3].…”

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A Study on the Interrelationship between the Microstructural Features and the Elevated Temperature Strength of Multicomponent Al-Si-Cu-Ni Casting Alloys

Jo¹,

Cho²,

Lee³

et al. 2022

Korean J. Met. Mater.

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The elevated temperature strength of multicomponent Al-Si alloys is greatly affected by the volume fraction and the interconnectivity of hard phases formed upon solidification. In the present investigation, such influences were examined for two Al-Si-Cu-Ni alloys with different total volume fractions of hard phases. To control the microstructural features related to the size of the phase, the specimens were prepared with and without ultrasonic melt treatment (UST) at different cooling rates. The microstructures of the alloys were composed of primary Si, eutectic Si, (Al,Si)3(Zr,Ni,Fe), Al9FeNi and Al3(Cu,Ni)2 phases. The microstructural features, such as the size and aspect ratio of each phase, changed with UST and cooling rate, and accordingly, the elevated temperature strength at 350 oC was changed. The alloy with a high volume fraction of about 30 vol.% exhibited increased elevated temperature strength at 350 oC when ultrasonic melt treated, and the alloy having a volume fraction as low as about 18 vol.% exhibited the opposite results. Considering the microstructural features of the multi-component Al-Si alloy, a hexagonal shear-lag model was suggested, based on the well-known shearlag model proposed by Nardone and Prewo (Scr. Metall. 20;1986:43-48). Using the 2-D microstructural factors such as the size, aspect ratio of the phase and secondary dendrite arm spacing, the elevated temperature strength was calculated and compared with the measured value. Based on the hexagonal shear-lag model, the influence of microstructural factors on the elevated temperature strength was discussed for multi-component Al-Si-Cu-Ni alloys.

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Effects of Melt Thermal-Rate Treatment on Fe-Containing Phases in Hypereutectic Al-Si Alloy

Cited by 20 publications

References 18 publications

Influência das variáveis de solidificação na microestrutura e microdureza de ligas Al-Cu utilizando planejamento fatorial complete

Influência das variáveis de solidificação na microestrutura e microdureza de ligas Al-Cu utilizando planejamento fatorial complete

Effect of Melt Overheating on Structure and Mechanical Properties of Al-Mg-Si Cast Alloy

A Study on the Interrelationship between the Microstructural Features and the Elevated Temperature Strength of Multicomponent Al-Si-Cu-Ni Casting Alloys

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