Article
Materials Science, Multidisciplinary
Tao Gao, Xu Zhao, Hongqian Xue, Zhidan Sun
Summary: The fracture surface characteristics and micromechanisms of fish-eye crack initiation in a Ti-6Al-4V alloy under VHCF loading were investigated. The crack initiation area exhibited ragged-like mountains, dimples, and various irregular rods/particles, grooves, and microvoids. These characteristics were primarily attributed to the nucleation and coalescence of microvoids and grooves at the alpha(s)/beta(r) interface inside the beta(trans). The beta(trans) played a dominant role in the fish-eye crack initiation and early propagation process.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Nanoscience & Nanotechnology
H. Zhang, M. Y. Zhao, J. F. Zhang, X. L. Zhao, F. Fang, N. Jia
Summary: In this study, a heavily N-doped FeMnCoCr high-entropy alloy with multiple heterostructures was prepared by mechanical alloying and spark plasma sintering. The alloy exhibited a high compressive yield strength and satisfactory fracture strain at room temperature.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Azmi Erdogan, Ali Gunen, Mustafa Sabri Gok, Sakin Zeytin
Summary: CoCrFeNiAl0.25Ti0.5 high entropy alloy alloys were borided to improve their mechanical properties, resulting in significant increases in surface hardness. However, increasing the boriding temperature led to thicker and harder boride layers, but decreased fracture toughness.
Article
Chemistry, Physical
Li Chen, Zhanjiang Li, Pinqiang Dai, Peixin Fu, Qunhua Tang, Junfeng Chen
Summary: The feasibility of preparing Fe50Mn30Co10Cr10 high-entropy alloys via powder metallurgy was explored, and the effect of sintering temperature and deformation temperature on the microstructure and tensile properties of the alloy was investigated. The best combination of strength and ductility was obtained in the alloy sintered at 1000 degrees C, with a strongly temperature-dependent mechanical behavior.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Myoung Jin Chae, Ashutosh Sharma, Min Chul Oh, Byungmin Ahn
Summary: In this study, a new AlCuFeMnMgTi lightweight high entropy alloy (LWHEA) was synthesized via high energy ball milling and spark plasma sintering (SPS). The effect of milling time and SPS conditions on microstructure, hardness, and density of LWHEAs was investigated. The results showed that the BCC2 phase fraction increased gradually after SPS, and porosity increased with longer milling time and higher SPS temperature. The presence of finer secondary phases in the HEA matrix contributed to dispersion hardening, resulting in optimum microhardness and density.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Sheetal Kumar Dewangan, Ornov Maulik, Devesh Kumar, Saurav Kumar, Vinod Kumar, Byungmin Ahn
Summary: In this study, the impact of heat treatments on AlFeCuCrMgx alloys prepared by mechanical alloying and spark plasma sintering was investigated. The phase evolution and microstructure changes of these alloys at different temperatures were studied using XRD, SEM, and TEM techniques.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Zhen Zhang, Qianqian Wang, Dikunqi Mu, Gaoyuan Shen, Mohan Liu, Mai Zhang, Sammy Lap Ip Chan, Jiamiao Liang, Jun Wang
Summary: The CoCrFeNiAl0.3 high entropy alloy samples were produced using different ball milling strategies, and the microstructure and phase formation were investigated. The study found that mechanical mixing resulted in a mixture of FCC and BCC structured matrix, as well as intermediate multiphases, while mechanical alloying produced a single phase FCC matrix. The microstructure exhibited good thermal stability, attributed to the pinning effects of dispersed Al2O3 nanoparticles. The Al2O3 nanoparticles played a dominant role in improving the mechanical properties.
MATERIALS CHARACTERIZATION
(2022)
Article
Green & Sustainable Science & Technology
M. Mucalo, L. Bolzoni, Y. Qu, A. Kumar, Y. Li, F. Yang
Summary: In this study, NiMnFeCrCu high entropy alloy (HEA) was synthesized and investigated for its application in the oxygen evolution reaction. The experimental results showed that the R4 HEA sample exhibited an overpotential of 310 mV under 100 cycles of cyclic voltammetry activation. The R4 HEA alloy had good combined properties of strength and activity, making it a potential self-supported electrocatalyst for industrial scale practical water electrolysis application.
MATERIALS TODAY SUSTAINABILITY
(2023)
Article
Nanoscience & Nanotechnology
Peyman Asghari-Rad, Praveen Sathiyamoorthi, Nhung Thi-Cam Nguyen, Alireza Zargaran, Taek Soo Kim, Hyoung Seop Kim
Summary: This study demonstrates a novel approach to achieve a high synergy of tensile strength and ductility in alloys fabricated by powder metallurgy, using high-pressure torsion and annealing. The results show exceptional tensile properties that have never been achieved before in this field, offering new possibilities for the fabrication of high-entropy alloys and composites.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
Wenshu Li, Bingfeng Wang, Xiaoxia Huang, Bin Liu, Jamieson Brechtl, Peter K. Liaw
Summary: Powder-metallurgy-fabricated CoCrFeMnNi high-entropy alloys (HEAs) show great potential for application in high-speed impact deformation due to their uniform microstructures and compositions. The mechanical behavior of the alloy at room temperature and under different strain rates was investigated, revealing the occurrence of serration behavior and shear localization. The study also found that the yield strength values of the alloy were sensitive to strain rates, with an increase observed as the strain rates increased. Shear bands with nanotwins and ultrafine-equiaxed grains were observed in the alloy, indicating higher strength compared to the matrix grain.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
Byungchul Kang, Taeyeong Kong, Nguyen Huy Dan, Doan Dinh Phuong, Ho Jin Ryu, Soon Hyung Hong
Summary: The addition of boron to a refractory high-entropy alloy (RHEA) significantly improves its yield strength and ductility, transforming the fracture surface and enhancing the material's ductility due to boron segregation along grain boundaries. Boron segregation contributes to increased grain boundary cohesion, leading to enhanced yield strength. The improved yield strength attributed to boron doping is a result of the combined effects of Orowan, dislocation, and boron interstitial strengthening mechanisms.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Tinghui Cao, Yake Wu, Jin Tian, Feng Jiang, Jun Sun
Summary: A method combining internal oxidation and powder forging was used to fabricate Fe40Mn40Co10Cr10 high-entropy alloy, in which submicro-scaled oxide particles were in-situ formed and distributed uniformly in the matrix. The prepared HEA exhibited excellent mechanical properties at room temperature and good thermal stability at high temperatures, showing better strength-ductility synergy than those prepared by conventional powder metallurgical methods.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Physical
Laura Elena Geambazu, Dorinel Talpeanu, Robert Viorel Bololoi, Ciprian Alexandru Manea, Alina Elena Bololoi, Florin Miculescu, Delia Patroi, Vasile Danut Cojocaru
Summary: Alloys with superior properties have been the focus of recent studies due to their effectiveness in reducing equipment maintenance costs and improving usage time. In this study, Al0.5CrFeNiTi alloy was produced by solid state processing in a planetary ball mill, and further processed by pressing and sintering. The results showed that mechanical alloying processing reduced the particle size of the metal powder, and the pressed and sintered samples had no major defects.
Article
Nanoscience & Nanotechnology
Cheenepalli Nagarjuna, Sheetal Kumar Dewangan, Hansung Lee, Byungmin Ahn
Summary: A novel equiatomic CrFeNiTiV high entropy alloy (HEA) was synthesized through mechanical alloying and spark plasma sintering, and the effects of heat treatment temperature on the phase stability and mechanical properties were investigated. The results showed that the phase and mechanical properties of the HEA were improved after heat treatment, making it suitable for high-temperature applications.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Hansung Lee, Ashutosh Sharma, Byungmin Ahn
Summary: This study investigates the influence of Si addition on the microstructure, compressive strength, and fracture mechanisms of FeCoNiAlSi high-entropy alloys (HEAs). The results show that the addition of Si changes the phase structure of the alloy and increases its Vickers hardness and compressive strength. The findings suggest that HEAs with different Si contents can be used for designing high-strength structural alloys for automotive applications.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Environmental
Rubaya Yeasmin, Seung-Ik Han, Le Thai Duy, Byungmin Ahn, Hyungtak Seo
Summary: This article introduces the development of a multifunctional self-healing, stretchable, deformable, biocompatible, transparent, and self-adhesive composite based on networking PBS (polyborosiloxane) and Ecoflex. The composite possesses fast self-healing capability, high stretchability, transparency, ideal electrical insulation, and good chemical stability. It also exhibits consistent thermal stability at high temperatures. These remarkable properties make it an essential skin-mimicking substrate for biomedical and wearable applications such as e-skin.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
Cheenepalli Nagarjuna, Sheetal Kumar Dewangan, Ashutosh Sharma, Kwan Lee, Soon-Jik Hong, Byungmin Ahn
Summary: An equiatomic CoCrFeMnNi high entropy alloy (HEA) was prepared by gas atomization process. High-energy milling was conducted to investigate the effects of milling parameters on the morphology and crystallographic properties of HEA powders. X-ray diffraction and scanning electron microscopy were used for phase identification and morphology observation of the milled powders. Both atomized and milled powders exhibited a single-phase face-centered cubic solid solution. The crystallite size (CS) decreased from 39.7 to 6.56 nm and the lattice strain (LS) increased from 0.25%-1.48% with increasing milling time from 0 to 240 min. Furthermore, an artificial neural network (ANN) approach provided accurate predictions of CS and LS with accuracies of 96.25% and 93.43%, respectively.
METALS AND MATERIALS INTERNATIONAL
(2023)
Article
Metallurgy & Metallurgical Engineering
Sheetal Kumar Dewangan, Cheenepalli Nagarjuna, Hansung Lee, Ashutosh Sharma, Byungmin Ahn
Summary: A preliminary study was conducted to investigate the impact of pressureless sintering on the surface morphology of AlFeCoNi alloy with the addition of Si element. The study aimed to determine the feasibility of achieving densification of high entropy alloys using conventional sintering techniques. The results showed that even with the addition of Si, the high entropy alloys maintained a single-phase BCC structure. Thermodynamic simulation (CALPHAD) was used to predict phase formation, and the effects of sintering temperatures on crystallite sizes and lattice strains were discussed. Densification mechanisms occurring at different sintering temperatures were also analyzed. While porosity was observed, the density of high entropy alloys improved with higher sintering temperatures.
Article
Metallurgy & Metallurgical Engineering
Hansung Lee, Ashutosh Sharma, Minsu Kim, Byungmin Ahn
Summary: This study investigated the effects of Cu addition on AlFeMnTiSi0.75Cux (x = 0, 0.25, 0.5, 0.75, 1.00) high entropy alloys (HEAs) prepared via mechanical alloying and spark plasma sintering. The analysis of the HEA powders revealed a multiphase structure. After sintering at 900°C, the formation of BCC, μ, and L2(1) phases in the densified HEAs was enhanced. The improved microstructural and mechanical properties were observed at the optimal Cu fraction (0.25 molar ratio).
Article
Metallurgy & Metallurgical Engineering
Cheenepalli Nagarjuna, Sheetal Kumar Dewangan, Kwan Lee, Byungmin Ahn
Summary: TiC-reinforced CoCrFeMnNi high-entropy alloy composites were prepared using mechanical alloying and spark plasma sintering. The study focused on the phase composition, microstructure, mechanical properties, and thermal expansion behavior of the composites. The addition of TiC did not affect the crystal structure, but had a significant influence on the microstructure and mechanical properties. Increasing TiC content resulted in decreased grain size, leading to enhanced hardness and compressive yield strength due to grain boundary and dispersion strengthening effects. The thermal expansion curves showed linear increments up to 800 degrees C and decreased with increasing TiC content.
Article
Pharmacology & Pharmacy
Surabhi Kumari, Anuj Nehra, Kshitij Gupta, Anu Puri, Vinay Kumar, Krishna Pal Singh, Mukesh Kumar, Ashutosh Sharma
Summary: The authors developed biocompatible nano-vesicles using graphene oxide (GO) for the targeted release of chlorambucil (CHL) drugs in cancer cells. GO sheets were functionalized with folic acid (FA) molecules to improve controlled release and loading efficiency of CHL. The drug was loaded onto the GO surface through pi-pi stacking and hydrophobic interactions. In vitro release studies showed a pH-dependent release, with faster release at lower pH.
Article
Nanoscience & Nanotechnology
Cheenepalli Nagarjuna, Sheetal Kumar Dewangan, Hansung Lee, Byungmin Ahn
Summary: A novel equiatomic CrFeNiTiV high entropy alloy (HEA) was synthesized through mechanical alloying and spark plasma sintering, and the effects of heat treatment temperature on the phase stability and mechanical properties were investigated. The results showed that the phase and mechanical properties of the HEA were improved after heat treatment, making it suitable for high-temperature applications.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
K. Raja Rao, Sheetal Kumar Dewangan, A. H. Seikh, Sudip Kumar Sinha, Byungmin Ahn
Summary: This study investigates the preparation of a high-entropy alloy through mechanical alloying and vacuum hot pressing, and examines the effect of different consolidation temperatures on the microstructure and hardness of the alloy.
METALS AND MATERIALS INTERNATIONAL
(2023)
Article
Metallurgy & Metallurgical Engineering
Hansung Lee, Minsu Kim, Ashutosh Sharma, Byungmin Ahn
Summary: This study investigated the dry sliding wear behavior of AlSi0.75TiMnFeCux (x = 0, 0.25, 0.5) high-entropy alloys (HEAs) prepared through mechanical alloying (MA) and spark plasma sintering (SPS). The microstructure and phase evolution were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The wear resistance of the HEAs was evaluated under dry air atmosphere using a reciprocating wear monitor. The results showed that the addition of Cu up to 0.25 molar ratio improved the microhardness and wear behavior of AlSi0.75TiMnFeCux HEAs, but beyond that, a mixed adhesive-abrasive wear mechanism dominated.
Article
Engineering, Mechanical
Hansung Lee, Ashutosh Sharma, Byungmin Ahn
Summary: The wear behavior of FeCoNiAlSi0.2 high-entropy alloy and Si-free FeCoNiAl in reciprocating sliding wear process for automotive piston rings was evaluated. Advanced powder metallurgy was used to prepare the high-entropy alloys to overcome the issues of shrinkage porosity, segregation defects, poor densification, and wear resistance. The morphology, hardness, wear, and friction properties were investigated.
Article
Materials Science, Multidisciplinary
Sheetal Kumar Dewangan, Ornov Maulik, Devesh Kumar, Saurav Kumar, Vinod Kumar, Byungmin Ahn
Summary: In this study, the impact of heat treatments on AlFeCuCrMgx alloys prepared by mechanical alloying and spark plasma sintering was investigated. The phase evolution and microstructure changes of these alloys at different temperatures were studied using XRD, SEM, and TEM techniques.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Neeraj Kumar, Ashutosh Sharma, M. K. Manoj, Byungmin Ahn
Summary: This study prepared self-lubricating aluminum matrix composites using powder metallurgy technique and evaluated their wear, coefficient of friction, and corrosion resistance under different conditions. The results demonstrated that the addition of MoS2 reduced wear and coefficient of friction while improving corrosion resistance. The effects of load and reinforcement concentration were more significant.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
