Microstructural Development of an AlNiBi Alloy and Influence of the Transient Horizontal Solidification Parameters on Microhardness

Azevedo, Hugo; Machado, Gabriel H.; Barbosa, Carolina R.; Rocha, Fernando S.; Costa, Rogério B.; Costa, Thiago A.; Rocha, Otávio Fernandes Lima da

doi:10.1007/s11661-018-4747-4

Cited by 11 publications

(11 citation statements)

References 53 publications

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“…(V L ) −2/3 and λ 2 = Constant. (T R ) −1/3 , respectively, whose exponents −2/3 and −1/3 are concordant with the literature for Al-based alloys [1,2,[10][11][12][16][17][18]27,28,[40][41][42][43]47,50,51]. Figure 6 also shows a comparative analysis between the results of this work and those reported by Costa et al [1], and an excellent agreement has been observed for the two assumed solution, despite a slight disagreement of the trend of λ 2 = f (P) found for the time equal to 8 h.…”

Section: Resultssupporting

confidence: 91%

“…The directional solidification device used in the experiments and a schematic heat transfer modes during horizontal solidification process are shown in Figure 1(a,b). The device has been detailed and published in your work [1,12,41]. As can be observed by Figure 1(a), the solidification set-up was designed in such a way that heat was extracted only through the water-cooled mould, promoting horizontal directional solidification.…”

Section: Methodsmentioning

confidence: 99%

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Interconnection between the solidification and precipitation hardening processes of an AlSiCu alloy

Magno

Souza

Costa

et al. 2019

Materials Science and Technology

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Horizontal directional solidification and precipitation hardening experiments were performed with the Al5.5Si3Cu alloy. Solidification thermal and microstructural parameters such as growth and cooling rates ( VL and TR, respectively) and the secondary dendrite arm spacing ( λ2) were determined experimentally. As-solidified samples were selected and submitted to the T6-heat treatment (T6-HT). The T6-HT was carried out considering two solution times: 8 and 5 h at 490 ± 2°C, followed by quenching in warm water (60 ± 2°C), aging for 5 h at 155 ± 2°C and air-cooling. Higher HV values were observed for the solution time of 5 h. As highlights of this work, the influence of the processing parameters ( VL, TR and λ2) on the distribution, morphology and size of the eutectic Si particles has been investigated.

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Section: Resultssupporting

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Interconnection between the solidification and precipitation hardening processes of an AlSiCu alloy

Magno

Souza

Costa

et al. 2019

Materials Science and Technology

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“…There is evidence of increased impact strength and reinforcement by lignin in addition to polymers including PMMA used in denture bases. 51 Many studies also support a correlation between nanoparticles acting as an inorganic filler phase directly enhancing mechanical properties of dental adhesives. 52 Shear Bond Strength Test.…”

Section: ■ Results and Discussionmentioning

confidence: 96%

“…This is an interesting finding revealing that lignin dispersion in nanoparticles imparts a positive mechanical aspect to RMGIC. There is evidence of increased impact strength and reinforcement by lignin in addition to polymers including PMMA used in denture bases . Many studies also support a correlation between nanoparticles acting as an inorganic filler phase directly enhancing mechanical properties of dental adhesives …”

Section: Resultsmentioning

confidence: 98%

Anticariogenic and Mechanical Characteristics of Resin-Modified Glass Ionomer Cement Containing Lignin-Decorated Zinc Oxide Nanoparticles

Malik

Muhammad

Kaleem

et al. 2023

ACS Appl. Bio Mater.

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This study aims to synthesize and characterize lignin-decorated zinc oxide nanoparticles before incorporating them into resin-modified glass ionomer cement (RMGIC) to improve their anticariogenic potential and mechanical properties (shear bond strength and microhardness). Probe sonication was used to synthesize lignin-decorated zinc oxide nanoparticles which were then characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Following characterization, these were incorporated in RMGIC (Gold label, Fuji II LC). Three major groups, experimental group A (EGA), experimental group B (EGB), and control group (CG), were outlined. EGA and EGB were divided into numbered subgroups based on the ascending concentrations of nanoparticles (5, 10, and 15%) of lignin-coated zinc oxide and zinc-oxide, respectively. CG served as a control and comprised cured RMGIC samples without any incorporation. Anticariogenic analysis was conducted on experimental RMGIC samples via disk-diffusion (n = 3) and direct contact test (n = 3) against Streptococcus mutans (ATCC 25175). Optical density values for days 1, 3, and 5 were recorded via a UV− Vis spectrophotometer. A shear bond strength test was performed using 35 premolars. The adhesive remnant index was used to estimate the site of bond failure. For the Vickers microhardness test (n = 3), 100 g of load at 10 s dwell time was set. Atomic absorption spectroscopy was performed over 28 days to determine the release of zinc from the samples. All tests were analyzed statistically. The anticariogenic potential of EGA and EGB was significantly greater (p ≤ 0.05) than that of the control. The shear bond strength test reported the highest value for EGA15 with all groups exhibiting failure at the bracket/RMGIC interface. The microhardness of EGA15 yielded the highest value (p ≤ 0.05). Release kinetics displayed a steady release with EGB15 exhibiting the highest value. The EGA and EGB samples displayed good anticariogenic potential, which was sustained for 28 days without any deleterious effect on the shear bond strength and microhardness.

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“…Esta diminuição da microdureza está diretamente correlacionada com alterações microestruturais decorrentes da transformação líquido/sólido, principalmente com o engrossamento da estrutura dendrítica em função do crescimento do sólido, conforme indicado por alguns autores [14,21,37]. Tal comportamento é justificado pelo fato de que o refinamento dos espaçamentos dendríticos impõe maior dificuldade à movimentação de discordâncias durante a deformação (indentação), justificando a obtenção dos maiores valores de microdureza para posições próximas a interface de resfriamento [14,33,38]. De maneira geral, pode-se notar a tendência de elevação da microdureza com a diminuição dos valores tanto de  1 como de  2 .…”

Section: Avaliação Estruturalunclassified

Liga hipoeutética Al-11%Si: coeficiente de transferência de calor interfacial, variáveis térmicas, parâmetros microestruturais e microdureza

Rodrigues¹,

Júnior²,

Barros³

et al. 2021

Matéria (Rio J.)

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RESUMO Este artigo apresenta um estudo teórico-experimental com o objetivo de determinar o coeficiente de transferência de calor interfacial, as variáveis térmicas de solidificação, os espaçamentos dendríticos primários e secundários bem como a microdureza Vickers da liga Al-11%Si solidificada direcionalmente, sob condições transientes de fluxo de calor, em um dispositivo de configuração horizontal refrigerado a água. Para o monitoramento dos perfis de temperatura utilizou-se um conjunto de termopares tipo K localizados em diferentes posições a partir da interface metal-molde, considerando a linha central correspondente ao eixo longitudinal do lingote. Uma técnica numérica, que compara perfis térmicos teóricos e experimentais, foi utilizada no cálculo do coeficiente de transferência de calor na interface metal/molde durante a solidificação cuja condição transiente é representada por uma equação analítica na forma de potência. Foram aplicadas técnicas experimentais para o cálculo das variáveis térmicas de solidificação, ou seja, deslocamento da frente de solidificação, velocidade da isoterma liquidus e taxa de resfriamento. Os resultados experimentais e simulados apresentaram uma concordância muito boa e possibilitaram estabelecer correlações analíticas entre tais variáveis térmicas e os espaçamentos dendríticos primários e secundários obtidos, por meio de equações na forma de potência representadas por expoentes característicos. Finalmente, são também apresentadas expressões experimentais capazes de correlacionar os valores dos espaçamentos dendríticos estudados com o comportamento da microdureza Vickers da referida liga.

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Microstructural Development of an AlNiBi Alloy and Influence of the Transient Horizontal Solidification Parameters on Microhardness

Cited by 11 publications

References 53 publications

Interconnection between the solidification and precipitation hardening processes of an AlSiCu alloy

Interconnection between the solidification and precipitation hardening processes of an AlSiCu alloy

Anticariogenic and Mechanical Characteristics of Resin-Modified Glass Ionomer Cement Containing Lignin-Decorated Zinc Oxide Nanoparticles

Liga hipoeutética Al-11%Si: coeficiente de transferência de calor interfacial, variáveis térmicas, parâmetros microestruturais e microdureza

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