Article
Green & Sustainable Science & Technology
Pengting Li, Lian Dong, Zhiqiang Hu, Shiqiang Ren, Yi Tan, Dachuan Jiang, Xiaogang You
Summary: This paper presents a method of using electron beam melting coupled with directional solidification to purify silicon scraps. Hard particles are effectively removed by the collision and clustering under the action of melt convection. Metal impurities are concentrated in the top center of the ingot due to the accelerated convection caused by the electron beam. The obtained silicon ingot has low impurity content and can be used for high-performance polycrystalline silicon production.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Engineering, Manufacturing
Shubham Chandra, Xipeng Tan, R. Lakshmi Narayan, Chengcheng Wang, Shu Beng Tor, Gerald Seet
Summary: The study found that severe intergranular hot cracking occurs in a Ni-based superalloy manufactured via selective electron beam melting (SEBM), and a generalized cracking criteria was developed to predict and prevent hot cracking while maintaining the desired microstructure. Results also showed that micro-segregation at divergent grain boundaries tends to promote cracking, but using the findings from this research could potentially mitigate hot cracking in additively manufactured Ni-based superalloy single crystals.
ADDITIVE MANUFACTURING
(2021)
Article
Engineering, Manufacturing
Narendran Raghavan, Benjamin C. Stump, Patxi Fernandez-Zelaia, Michael M. Kirka, Srdjan Simunovic
Summary: This study investigates the correlation between spot-melt scan parameters, build geometry, and solidification microstructure evolution in a powder bed fusion technology. It is found that adjusting the areal energy density per layer with respect to the 2D cross-sectional area is necessary to maintain equiaxed solidification microstructure in electron beam powder bed additive manufacturing. Increasing areal energy density transitioned the solidification microstructure from columnar to equiaxed, and the observed microstructure data was quantified using a spatial statistics methodology. Additionally, a semi-analytical model was used to simulate heat transfer and solidification conditions, which was correlated with previously quantified microstructure data.
ADDITIVE MANUFACTURING
(2021)
Article
Engineering, Chemical
Yuan Gao, Yi Tan, Wenliang Qi, Zhiqiang Hu, Pengting Li
Summary: Removing stubborn B from Si efficiently and simplifying the purification process are critical challenges in the manufacture of solar grade silicon via metallurgical routes. This study presents a method to address these challenges by flexibly coupling B with other impurities separation procedure, and purifying metallurgical grade silicon through simplified electron beam melting unlocked by a few oxides. The method not only ensures the smooth process of B oxidation, but also favors the co-removal of other impurities, achieving high purity Si.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Green & Sustainable Science & Technology
Mahdi Kazemi, Ali Kianifar, Hamid Niazmand
Summary: The research aimed to investigate the feasibility of using phase change material (PCM) to fabricate an air-PCM heat exchanger for buildings, showing that nano-PCMs can improve heat transfer efficiency and reduce melting and solidification time.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Engineering, Chemical
Yufan Zhao, Kenta Aoyagi, Yujie Cui, Kenta Yamanaka, Akihiko Chiba
Summary: The quality of powder bed fusion (PBF) products is influenced by processing conditions and materials, with powder characteristics playing a significant role in determining packing features and affecting heat transfer processes. This study focused on the influence of powder characteristics on upper surface quality and solidification grain structure in PBF with electron beam (PBF-EB) using two types of CoCrMo alloy powders with different thermal conductivities. The results showed that powder with high thermal conductivity alleviated overheating under high-power conditions and improved fusion sufficiency under low-power conditions.
Article
Materials Science, Multidisciplinary
S. Tao, R. Gao, H. Peng, H. Guo, B. Chen
Summary: This study demonstrates the successful repair of CMSX-4 single crystals using powder-bed fusion additive manufacturing technology, achieving a fine columnar dendritic substructure, limited in-grain misorientation, and strong deposit-to-substrate bonding.
MATERIALS & DESIGN
(2022)
Article
Thermodynamics
Takashi Morimoto, Hiroyuki Kumano
Summary: PCM emulsions (PCMEs) with high fluidity and thermal energy storage density have attracted attention for their potential use in thermal energy storage and transport. This study experimentally investigated the natural convection and heat transfer characteristics of PCMEs in a rectangular vessel. Multiple convection layers were observed in PCMEs due to the phase change of PCM particles. The aspect ratio of the vessel did not affect the formation of multiple convection layers. Heat transfer was promoted in PCMEs when accompanied by a PCM particle phase change, and the effect was most remarkable when the aspect ratio was 3.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Mechanics
Yoram Kozak
Summary: This study investigates the close-contact melting of a vertical cylinder on a horizontal isothermal superhydrophobic surface using a numerical and analytical model. The results show that superhydrophobic surfaces can extend the melting time by up to 30% due to the effect of hydrodynamic slip. However, the heat transfer rate is significantly reduced and the melting time is roughly doubled due to the dominant effect of thermal slip.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Virkeshwar Kumar, Atul Srivastava, Shyamprasad Karagadde
Summary: This study investigates natural convection patterns in various compositional regimes of a typical ternary system, as well as the impact of microstructure on natural convection. Flow observations show convection occurring in the form of plumes, random mixing, and double-diffusive layering, with the occurrence of Rayleigh-Taylor instability varying with the heavier component.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Chemistry, Physical
Jean-Pierre Bellot, Julien Jourdan, Jean-Sebastien Kroll-Rabotin, Thibault Quatravaux, Alain Jardy
Summary: The Electron Beam Melting (EBM) process can enhance the removal of exogenous inclusions in titanium alloys and the melting rate is nearly proportional to the EB power. It was found that the overheating temperature remains roughly independent of the melting rate and equal to about 100 degrees C.
Review
Engineering, Manufacturing
Necati Ucak, Adem cicek, Kubilay Aslantas
Summary: In recent years, additive manufacturing (AM) of metallic parts has provided new opportunities for various industrial sectors and individual needs. While AM offers many advantages, poor surface quality of the produced parts is a common issue that requires additional machining operations. This review article investigates the machinability of 3D printed metallic parts fabricated by Selective Laser Melting (SLM) and Electron Beam Melting (EBM) technologies, and provides insights into their mechanical and physical properties. The article aims to compile relevant information and suggest machining strategies for these novel engineering materials, as well as highlight potential areas for future research.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Nanoscience & Nanotechnology
Y. Yao, C. Xing, H. Peng, H. Guo, B. Chen
Summary: Selective electron beam melting (SEBM) was used to process crack-free Ni3Al-based IC21 alloy with similar to 85% gamma'-volume fraction. The segregation of Si to low melting point liquid films enhances the susceptibility to solidification cracking in IC21 produced by SEBM. Tensile specimens extracted from the crack-free IC21 samples exhibit superior properties at room temperature and 1000 degrees C, with different deformation mechanisms observed at these temperatures.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Bang Xiao, Wenpeng Jia, Huiping Tang, Jian Wang, Lian Zhou
Summary: WMoTaNbTi RHEAs formed by SEBM with negative defocus distance were studied. The results show that the decrease in scanning speed leads to vaporization of Nb and Ti elements, weakening the solid-solute strengthening and reducing the content of Nb and Ti solutes in the matrix, resulting in improved ductility and decreased microhardness. The as-deposited WMoTaNbTi RHEA formed at a scanning speed of 2.5 m/s exhibits high ultimate strength.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Wenyi Yang, D. D. L. Chung
Summary: This study investigated the effect of cooling rate on the electrical behavior of solidified solder, finding that ice-water quenching resulted in finer microstructure and higher resistivity compared to air cooling, while the permittivity remained unchanged. The microstructural refinement from quenching decreased mobility without affecting the carrier-atom interaction responsible for permittivity.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Materials Science, Multidisciplinary
Ping Zhang, Xiujie Yue, Yeran Gao, Zhenyong Lin, Shunxiang Wang, Songting Zhang
Summary: This paper investigates the strengthening mechanism of highspeed cutting and solid particle-entrained waterjet peening (HSC-WJP) composite reinforcement on 7075-T6 aluminum alloy. The research results show that composite reinforcement can improve surface quality, reduce surface pits and roughness, and decrease the size of precipitation-free zone (PFZ) at grain boundaries.
Article
Materials Science, Multidisciplinary
Sangyoon Lee, Hwi Yoon, Sanghun Lee, Seung-min Chung, Hyungjun Kim
Summary: The wettability of metal oxides, particularly HfO2 thin films deposited via atomic layer deposition, and its correlation with surface free energy have been studied. It was found that surface oxygen species significantly affect the intrinsic hydrophilicity of HfO2 thin films, and the crystalline orientations also evolve with film thickness.
Article
Materials Science, Multidisciplinary
Changdong Yin, Yiwen Wu, Zhou Xu, Dongdong Ye, Jun Yao, Jianjun Chen, Qiang Liu, Xin Ge, Meiling Ding
Summary: This study proposed a new strategy to indirectly estimate the hydrogen diffusivity of metallic materials under tensile stress by combining the electrochemical hydrogen permeation test (EHPT), the hydrogen diffusion descriptive equation based on Fick's law, and hydrogen pre-charged tensile test. The results showed that the hydrogen permeation curve obtained was highly approximate to the theoretical trend. The hydrogen embrittlement (HE) susceptibility of the specimens increased with increasing stress.
Article
Materials Science, Multidisciplinary
Huan Luo, Wei-yi Wang, Xin Yu, Xian-jun Lei, Lang Liu, Guo-zheng Zha, Wen-long Jiang, Bin Yang, Bao-qiang Xu
Summary: Separating selenium and tellurium is a general challenge in material and non-ferrous metallurgical industries. This paper proposes a novel method that achieved efficient separation of selenium and tellurium using gas-liquid equilibrium phase diagram and valence regulation-vacuum gasification technique.
Article
Materials Science, Multidisciplinary
Fan Zhang, Rong Xin Wang, Aiqin Tian, Fangzhi Li, Jianping Liu, Hui Yang
Summary: Deposition of Pd/Pt/Au three-layer films on p-GaN under high and ultra-high vacuum conditions was studied to investigate the electrical contact properties. Linear I-V curves were observed in samples deposited under ultra-high vacuum conditions, while nonlinear I-V characteristics were obtained in samples deposited under high vacuum conditions. The study also found that the samples deposited under high vacuum conditions had higher amounts of oxygen and Pd oxide. The oxide layer had an additional influence on the electrical characteristics of the Pd/Pt/Au/p-GaN contact.
Article
Materials Science, Multidisciplinary
Hongli Liu, Chengzhe Liu, Ying Sui, Zhongxian Liu, Tiangang Zhang, Zhiqiang Zhang, Shuang Sun, Jianwei Jia
Summary: This study utilized polysiloxane and hafnium carbide to produce Si-N-C-O-Hf hybridized ceramic fibers, and obtained ceramic fibers with hemispherical particles on the surface through electrostatic spinning and pyrolysis. The ceramic fibers exhibited excellent thermal stability, oxidation resistance, and high temperature insulation.
Article
Materials Science, Multidisciplinary
M. Abaker, Nazar Elamin Ahmed, A. Saad, H. F. Khalil, E. M. M. Ibrahim, A. M. Adam
Summary: This paper systematically studied the internal structure and thermoelectric properties of In1-xGaxSb alloys prepared by melting synthesis at 1123 K. The results showed that doping with Ga in the In sites led to a significant increase in the Seebeck coefficient and power factor, while reducing the thermal conductivity. The maximum dimensionless figure of merit was observed at 403 K.
Article
Materials Science, Multidisciplinary
Fucheng Yu, Jinlong Ren, Jielin Zhang, Haiyang Chen, Xin Tian, Chenchen Feng, Cuixia Li, Jianbin Zhang, Xianxi Tang, Xiaogang Hou
Summary: An environmentally friendly ZnO@BiVO4 composite photocatalyst was prepared using in-situ self-assembly and solvothermal methods, demonstrating good photocatalytic performance. The mass ratio of BiVO4 and NCZ was found to influence the photocatalytic performance of the composite.
Article
Materials Science, Multidisciplinary
Yaoming Shao, Pingping Zheng, Tianhao Dong, Lianghuan Wei, Haifei Wu, Jianxiao Si
Summary: In this paper, Mg3Bi2 films were prepared on glass substrate using magnetron sputtering, and the phase composition and thermoelectric properties of the films were investigated with different atomic ratios. The films displayed a metastable cubic phase and high conductivity when the atomic ratio exceeded stoichiometry.
Article
Materials Science, Multidisciplinary
I. V. Uimanov, D. L. Shmelev, S. A. Barengolts
Summary: A two-dimensional axisymmetric model has been developed to study the prebreakdown processes in a cathode microprotrusion under an external electric field. The simulation results show that electrohydrodynamic instability leads to the formation of a nanometer-sized conical protrusion on the microprotrusion tip, significantly accelerating the heating process.
Article
Materials Science, Multidisciplinary
Weilun Zhang, Di Yang, Feng Gong, Yongjun Chen, Tian Chen, Zhiwen Xie, Sirui Yang
Summary: A novel Pt doping method was designed to improve the thermal stability of CrWN coating. The doping of Pt atoms effectively blocks the coherent growth of the grains and creates a significant mixing effect, resulting in a smooth surface with uniform element distribution.
Article
Materials Science, Multidisciplinary
Xiaoye Wang, Xiaoguang Yang, Wenna Du, Tao Yang
Summary: In this study, the effects of multiple growth parameters on self-catalyzed growth of InAs/GaSb axial heterostructured nanowires on Si substrate by MOCVD were investigated. It was found that the growth temperature and switching time have significant influences on the nanowire growth.
Article
Materials Science, Multidisciplinary
Weizhong Cui, Yan Zhao, Can Cui, Xing Liu, Beili Pang, Jianguang Feng, Hongzhou Dong, Liyan Yu, Lifeng Dong
Summary: This study introduces Co2+ cations into Cs2AgBiBr6 film to improve its quality, grain size, and conductivity, resulting in enhanced solar cell efficiency.
Article
Materials Science, Multidisciplinary
Jian Wang, Ke Yang, Xianming Cheng, Yalin Lu, Ganghui Wu, Yang Zhang, Yun Kan
Summary: The corrosion behavior and microstructural evolution of Sc microalloyed Al-3.2Cu-1.5Li alloys were investigated in detail. The microstructural results showed higher levels of dislocations density in the Sc microalloyed sample, which resulted in significantly refined grains and T1 precipitates. Microalloying with Sc changed the corrosion mode of the alloy and localized corrosion was found to occur preferentially at the subgrain within unrecrystallized grains with high grain stored energy.
Article
Materials Science, Multidisciplinary
Weifeng Liu, Na Liu, Kaiqiang Song, Meiqin Zeng, Zhongchen Lu
Summary: Monoclinic WO3 prepared through plasma milling exhibits higher photocatalytic activity due to its higher surface area, increased oxygen vacancies, and defects.