Article
Metallurgy & Metallurgical Engineering
Zhenqiang Deng, Yaqiang Li, Pengcheng Sheng, Lukuo Hong, Nan Zhang, Mengfan Li
Summary: The solidification structure of peritectic steels (15CrMo and 20CrMo) were investigated through directional solidification experiments. Island dendritic structure was observed in the hypoperitectic steel (15CrMo) at different growth velocities. Traditional peritectic dendritic structure was observed in the hyperperitectic steel (20CrMo) at certain growth velocities, while an island dendrite structure was observed at a higher growth velocity. The solute distributions near the liquid-solid interface during solidification revealed the influence of steel grade and cooling velocity on the formation of island dendrite structures. Hypoperitectic steel is more prone to the formation of island dendrite structures compared to hyperperitectic steel.
IRONMAKING & STEELMAKING
(2023)
Article
Materials Science, Multidisciplinary
Peng Peng, Anqiao Zhang, Jinmian Yue, Xudong Zhang, Yuanli Xu
Summary: The research found that freckle formation in peritectic solidification mainly occurs in region I before the peritectic reaction and region II after the peritectic reaction, with more freckles observed at lower growth velocities. The theoretical Rayleigh number R-aP can effectively describe the relationship between freckle formation and growth velocity.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Metallurgy & Metallurgical Engineering
Adilson Vitor Rodrigues, Thiago Soares Lima, Talita Almeida Vida, Crystopher Brito, Amauri Garcia, Noe Cheung
Summary: The effects of adding 5.0 wt.% Ni to an Al-6wt.%Cu alloy on solidification cooling rate, growth rate, microstructure characteristics, morphology/distribution of intermetallic compounds (IMCs), and properties were investigated. Experimental growth laws were derived relating dendritic spacings with cooling rate and growth rate. The addition of Ni in the alloy composition provided a reinforcing effect surpassing that of microstructure refinement. Samples with thin, evenly distributed IMCs formed under higher cooling rates showed the highest corrosion resistance.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2021)
Article
Chemistry, Physical
D. Ezemenaka, C. Patino, A. Genau
Summary: This research focuses on the microstructure evolution and pattern formation in multi-component, multi-phase metallic materials during freezing, specifically investigating the solidification behavior of the three-phase Al-Cu-Mg eutectic. Results show that the stability of three-phase coupled growth in this system is influenced by velocity, gradient, and composition, with comparisons made to thermodynamically predicted values. Unlike the related Al-Ag-Cu eutectic system, thermal gradient was found to have no measurable effect on eutectic spacing or pattern in this study.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Metallurgy & Metallurgical Engineering
Peng Peng, Sheng-yuan Li, Wan-chao Zheng, Li Lu, Shu-dong Zhou
Summary: In this study, it was found that freckles in the dendritic mushy zone of Sn-Ni peritectic alloys are formed in two different regions before and after the peritectic reaction during directional solidification. Experimental results indicate that dendritic morphology is influenced by temperature gradient zone melting and Gibbs-Thomson effects, with a new Rayleigh number RaP proposed to consider both effects and the peritectic reaction. The prediction of RaP confirms freckle formation in two regions during peritectic solidification and heavier thermosolutal convection in samples with larger diameter.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2021)
Article
Metallurgy & Metallurgical Engineering
Peng Peng, Bi-zhou Zhao, Jia-tai Wang, Xing Pei, Zi-jie Liu, Lu Gan, Sheng-yuan Li
Summary: The hexagonal to orthorhombic phase transformation in Sn-Ni peritectic alloys was confirmed, and the morphological feature of this transformation was found to affect the diffusion distance of the remelting/resolidification process. A diffusion-based model was established to predict the restriction of the remelting/resolidification process and the variation of local rates.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2022)
Article
Materials Science, Multidisciplinary
Jinmian Yue, Peng Peng, Anqiao Zhang, Shengyuan Li, Wanchao Zheng, Li Lu, Shudong Zhou
Summary: In this study, directional solidification method was used to investigate the growth characteristics of intermetallic compounds in Sn-9at.%Co peritectic alloy. The transition of the leading phase was found to occur at a distance that increased with growth velocity, and the hardness was observed to increase with growth velocity as well.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Chemistry, Physical
Chunjuan Cui, Kai Zhang, Chongyang Wu, Yuanyuan Lai, Yan Wang, Haijun Su
Summary: This paper studied the high-temperature oxidation behavior of Fe(Al,Ta)/Fe2Ta(Al) eutectic composite and analyzed the mechanism from the perspective of kinetics and thermodynamics. The results showed that the eutectic composite undergoes oxidation at high temperatures, but a dense oxide film is not formed due to the low aluminum content.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Metallurgy & Metallurgical Engineering
Li Yanqiang, Zhao Jiuzhou, Jiang Hongxiang, He Jie
Summary: The solidification process and microstructure evolution of Pb-Al alloy have been studied. It was found that a supercooling zone exists in front of the solidification interface, where liquid-solid phase separation occurs. Al-rich particles form and grow by solute diffusion from the melt towards the solidification interface. Increasing the solidification rate increases the nucleation rate and number density of the Al-rich particles, while decreasing the average radius. The Stokes movement velocity of the Al-rich particles is in the same direction as the melt's solidification velocity, resulting in enrichment of Al-rich particles in front of the solidification interface.
ACTA METALLURGICA SINICA
(2022)
Article
Materials Science, Multidisciplinary
Rafael V. Lantmann, Andre M. S. Mariante, Tiago V. Pinheiro, Eleani M. da Costa, Carlos A. dos Santos
Summary: The thermal profile, microstructure, hardness, and wear response of Al-Cu alloys with different Cu and Cr contents were investigated. The addition of Cu and Cr affected the solidification process and hardness of the alloys. Cu decreased cooling rates while Cr increased cooling rates. The refinement of the microstructure enhanced the hardness, with the highest value achieved in the Al-4.5Cu-0.50Cr alloy. The wear response varied with the Cu content, with improved wear resistance for 2.5% Cu alloys and opposite behavior for 4.5% Cu alloys.
Article
Materials Science, Multidisciplinary
I Yilmazer, E. Cadirli, H. Kaya, U. Buyuk
Summary: Al-1.9Mn-5Fe (wt.%) alloy was prepared by adding 5 wt.% Fe to the eutectic Al-Mn alloy and underwent controlled solidification under four different growth velocities. Microhardness and ultimate tensile strength increased with increasing growth velocity or decreasing eutectic spacing, while elongation decreased. Relationships between these parameters were investigated using linear regression analysis. The microstructure, microhardness, tensile strength, and electrical resistivity were found to be affected by both eutectic spacing and growth velocity.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2021)
Article
Materials Science, Multidisciplinary
Guan Liu, Dong Du, Kaiming Wang, Ze Pu, Dongqi Zhang, Baohua Chang
Summary: In this study, the microstructures and wear behavior of the IC10 directionally solidified superalloy repaired by directed energy deposition process were investigated. It was found that the deposited layers exhibited a strong <001>-fiber texture in the building direction, with continuously increasing texture intensity. Different gamma' phases were observed in the heat-affected zone, while the deposit layers showed smaller gamma' phase sizes compared to the substrate and HAZ. The wear resistance varied among different zones, with the substrate showing the best wear resistance and the HAZ exhibiting the worst.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Physical
Anqiao Zhang, Peng Peng, Wanchao Zheng, Jieren Yang, Xudong Zhang, Yuanli Xu
Summary: In this study, directional solidification method was used to investigate the growth characteristics of intermetallic compounds in Cu-68at.%Sn alloys. The research found that growth velocity affects the transition of primary phase, and conclusions about phase transition velocity and properties were obtained through the Interface Response Function and hardness testing.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Crystallography
Masoud Ghods, Supriya R. Upadhyay, Ravi S. Rajamure, Surendra N. Tewari, Richard N. Grugel, David R. Poirier, Mark Lauer
Summary: The MICAST project involved directionally solidifying Al-7 wt% Si samples aboard the ISS to study the effect of mitigating convection on the primary dendrite array morphology. Results showed good agreement with predictions from the Hunt-Lu numerical model, especially in the steady-state growth regime.
JOURNAL OF CRYSTAL GROWTH
(2021)
Article
Chemistry, Physical
Erkan Ustun, Emin Cadirli
Summary: This paper systematically studied the microstructure evolution, microhardness, and tensile properties of Al-8.8La-1.2Ni ternary alloy under various solidification rates. The results showed that the solidification rate significantly influenced both the microstructure and mechanical properties of the alloy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Adilson Rodrigues, Rafael Kakitani, Ricardo Oliveira, Andre Barros, Crystopher Brito, Amauri Garcia, Noe Cheung
Summary: This study investigates the microstructure evolution and hardness variation of Al-15Cu-5Ni alloy using an unsteady-state directional solidification technique. The results reveal the presence of two-phase dendrites with a trefoil morphology and interdendritic regions composed of bimodal structures of Al7Cu4Ni and α-Al + Al2Cu. Experimental equations are proposed to describe the microstructure evolution and dendritic arm spacing growth.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2022)
Article
Materials Science, Multidisciplinary
Rafael Kakitani, Camila Konno, Amauri Garcia, Noe Cheung
Summary: This study investigates the effects of solidification cooling and growth rates on the microstructure and hardness of Al-Si-Zn alloys, showing that the addition of Zn improves mechanical properties and coarsening of dendrites increases hardness. The main mechanism of reinforcement is related to the supersaturated solid solution.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2022)
Article
Automation & Control Systems
Danusa Araujo de Moura, Guilherme Lisboa de Gouveia, Gustavo Figueira, Amauri Garcia, Piter Gargarella, Jose Eduardo Spinelli
Summary: AlSi10Mg alloys are widely used in various industries due to their desirable properties. In this study, Ni was added to modify the mechanical properties of the alloys. The solidification and cooling rates of the alloys were investigated using directional solidification and laser surface remelting processes. The results showed that the addition of Ni increased the cooling rates in the laser molten pools, leading to improved microstructural and hardness changes in the treated zones.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Computer Science, Artificial Intelligence
Carlos Henrique da Silva-Santos, Pedro Roberto Goulart, Felipe Bertelli, Amauri Garcia, Noe Cheung
Summary: One of the most important parameters in castings design is the heat transfer coefficient at the casting/mold surface. In this study, four different nature inspired algorithms were integrated into a numerical model to solve the inverse heat transfer problem and reduce the number of iterations for successful results.
JOURNAL OF INTELLIGENT MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
Sarah Maria de Albuquerque Sousa, Felipe Escher Saldanha, Guilherme Lisboa de Gouveia, Amauri Garcia, Jose Eduardo Spinelli
Summary: This article investigates the interaction of grain refiner and cooling rate on grain size, SDAS, and grain shape in the 6201 alloy. It is found that the grain size of the 6201 + NbB alloy associated with rapid solidification is roughly 7 times smaller than that associated with slow solidification. Furthermore, alpha-Al cells are generated for GS/SDAS ratio below and equal to 6, regardless of the processing method.
Article
Thermodynamics
I. L. Ferreira, A. Garcia, A. L. S. Moreira
Summary: A closed-form analytical solution is proposed for the transient solidification process of multicomponent alloys. This solution analytically solves the microscale solidification and provides the necessary local conditions for the evolution of macroscopic solidus, liquidus, and eutectic interfaces. The solution includes expressions for critical radius, total free energy, and nucleation rate based on recent theories, as well as a general solution for interface evolution that considers local temperature and concentration conditions for the proper integration of macroscopic temperature.
INTERNATIONAL JOURNAL OF THERMOPHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Danusa Araujo de Moura, Leonardo Fernandes Gomes, Claudio Alves Siqueira, Amauri Garcia, Jose Eduardo Spinelli
Summary: Increasing the Bi content in Al alloys improves wear resistance but reduces hardness. The wider distribution of Bi areas in the Al-rich phase contributes to the enhancement of wear resistance.
MATERIALS SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Bruno Silva Sobral, Pamala Samara Vieira, Thiago Soares Lima, Jose Eduardo Spinelli, Noe Cheung, Amauri Garcia, Bismarck Luiz Silva
Summary: In this study, the effects of different weight percentages of zinc additions on the microstructure and microhardness of Sn-3.5 wt% Ag alloy were investigated. It was found that the addition of zinc improved the microstructure and microhardness of the alloy.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Marcelino Dias, Abdoul Aziz Bogno, Jose Eduardo Spinelli, Ricardo Oliveira, Noe Cheung, Amauri Garcia, Hani Henein
Summary: This study explores the effect of adding bismuth to Al-8 wt%Si alloys and finds that bismuth can improve the machining and wear properties of the alloys. Bismuth modification influences the microstructural features, resulting in increased hardness. The impact of bismuth depends on the cooling rate.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Automation & Control Systems
Argos Soares Silva, Sarah Maria de Albuquerque Sousa, Guilherme Lisboa de Gouveia, Amauri Garcia, Jose Eduardo Spinelli
Summary: The effects of NbB addition on grain size, secondary dendrite arm spacing, and hardness of 2017 alloy samples were investigated. The results showed that the grain size decreased while the secondary dendrite arm spacing increased in DS samples, under similar cooling rates. Moreover, the grain size had little influence on the hardness of the alloys studied.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
R. Kakitani, A. P. Carrara, F. E. Mariani, N. C. Verissimo, L. C. Casteletti, A. Garcia, N. Cheung
Summary: The present study investigates the microstructure evolution of a directionally solidified Al-8wt.%Ni hypereutectic alloy and its impact on the balance of tensile, wear, and corrosion properties. It is found that a columnar region with eutectic colonies characterized by Al3Ni fibers + alpha-Al matrix is associated with higher solidification cooling rates (T) above 4.8°C/s. On the other hand, lower cooling rates result in equiaxed grains consisting of the primary Al3Ni phase distributed in the eutectic colonies. Experimental values of tensile, wear, and corrosion properties are related to each microstructure type (eutectic colonies and Al3Ni + eutectic colonies), showing distinct behaviors.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Thomas J. Obara, Raphael O. Minei, Rafael Kakitani, Jose E. Spinelli, Amauri Garcia, Noe Cheung
Summary: The effects of Nb and Sb microaddition and solidification cooling rate on the dendritic microstructure of Al-Si alloys were evaluated using a nonsteady-state directional solidification technique. Sb was found to reduce the primary dendritic spacing, while Nb did not have this effect. Eutectic Si modification occurred at high cooling rates, transforming into fibrous, branched, and globular forms. The Nb-containing alloy exhibited the highest hardness, and the tensile properties were correlated with changes in the primary dendritic spacing.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2023)
Article
Thermodynamics
Denis Silva Grillo Elesbao, Rafael Kakitani, Noe Cheung, Amauri Garcia, Vinicius Karlinski de Barcellos, Eleani Maria da Costa, Carlos Alexandre dos Santos
Summary: This study investigates the solidification path and microstructure formation of hypoeutectic Al-(2.5, 3.5, 4.5)Cu alloys with different Cu-Cr ratios. It is found that the addition of Cr refines the microstructure and increases the microhardness of the alloys as the Cu and Cr contents increase.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Materials Science, Multidisciplinary
Clarissa Cruz, Thiago Soares, Andre Barros, Amauri Garcia, Noe Cheung
Summary: This study investigates the interfacial heat transfer characteristics, microstructure, and tensile strength of Sn-Mg alloys on electronic substrates. The results show that the Ni substrate has higher interfacial thermal conductance compared to the Cu substrate due to metallurgical interaction.
Article
Chemistry, Physical
Talita Vida, Clarissa Cruz, Andre Barros, Noe Cheung, Crystopher Brito, Amauri Garcia
Summary: This study investigates the influence of Mn addition on the corrosion behavior of zinc alloys and finds that Mn addition significantly increases the corrosion activity and susceptibility. Coarsening of the microstructure promotes an acceleration of the corrosion rate.