Article
Chemistry, Physical
Hang Xue, Chong Yang, Frederic De Geuser, Peng Zhang, Jinyu Zhang, Bin Chen, Fuzhu Liu, Yong Peng, Jianjun Bian, Gang Liu, Alexis Deschamps, Jun Sun
Summary: Lightweight design and advanced energy applications require high-strength Al alloys for high-temperature use. However, current commercial high-strength Al alloys are limited to low-temperature applications due to difficulties in achieving both high thermal stability and large volume fraction of coherent nanoprecipitates. In this study, we demonstrate a strategy to stabilize coherent nanoprecipitates in Sc-added Al-Cu-Mg-Ag alloys, resulting in exceptional creep resistance and tensile strength at 400 degrees C. The formation of the stable nanoprecipitates is triggered by ledge-aided in situ phase transformation between slow-diffusing Sc and fast-diffusing Cu atoms. This method shows promise for the development of advanced high-temperature light alloys for large-scale industrial production.
Article
Materials Science, Multidisciplinary
Oscar A. Torres-Matheus, R. Edwin Garcia, Catherine M. Bishop
Summary: A novel multiphase field model was used to analyze the phase coexistence of tetragonal and rhombohedral phases in Pb-free BZT-40BCT. The study predicted metastable coexistence between the two phases, with domain microstructures exhibiting faceted domain walls and curved T-R phase interfaces near the polymorphic phase boundary. The miniaturization of domain structures near the boundary is due to low interfacial energies and a pinning effect from a large metastable phase fraction.
Article
Chemistry, Physical
Kaiwei Zhang, Feng He, Zhongsheng Yang, Dingcong Cui, Junjie Li, Zenan Yang, Jincheng Wang, Zhijun Wang
Summary: The study found that Re and Ru have certain effects on the stability and coarsening kinetics of the L1(2) phase in the Ni29Co27Fe27Cr3Al7Ti7 high entropy alloy. Both Re and Ru can promote the formation of L2(1) precipitates, and they reduce the coarsening rate of the L1(2) phase by slowing down atomic diffusion.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
J. Svoboda, G. A. Zickler, E. Kozeschnik, F. D. Fischer
Summary: Coarsening of objects, such as grains or precipitates, is a critical process in the heat treatment and high-temperature application of materials. Evolution equations, represented by stationary radius distribution functions, can be used to describe this coarsening process based on appropriate models that incorporate relevant phenomena. The proposed two-parametric family of evolution equations includes the Lifshitz, Slyozov and Wagner (LSW) theory as a special case and allows for the incorporation of specific phenomena controlling object evolution.
Article
Chemistry, Physical
Hongchang Zhao, Zixi Wang, Xi Han, Mingjia Wang
Summary: This study investigated the precipitation and growth mechanism of the Laves phase and the coarsening behaviors of Laves phase, M23C6, and MX carbonitrides in P91 steel at 625 degrees C. It was found that the Laves phase grew rapidly near the M23C6 carbide and exhibited a specific crystallographic orientation relationship. Additionally, the study observed the coarsening rates of these phases.
Article
Mechanics
Arghya Das, Mustansir Barma
Summary: Models of particles driven by a one-dimensional fluctuating surface exhibit fluctuation dominated phase ordering (FDPO), with macroscopic order and fluctuations appearing on large scales. Interfacial regions between ordered regions contain many domain walls, violating the Porod law. The total number of domain walls and the length of the largest ordered domain quantify the unique characteristics of FDPO. The study focuses on coarse-grained depth (CD) models and shows that domain wall number fluctuations remain constant during coarsening, while the length of the largest cluster grows with time and system size following a power law with logarithmic terms.
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2023)
Article
Chemistry, Physical
Xin Yu, Yang Bai, Bing Ye, Liyang Wang, Beibei Zhao, Xiangyang Kong
Summary: The thermal stability and grain growth kinetics of a high-pressure die casting Mg-6Y-3Zn-1Al alloy with long-period stacking ordered phase were studied through subsequent annealing at different temperatures. The results showed that the microstructure of the alloy was thermally stable up to 450 degrees C. The grain growth kinetics between 450 degrees C and 550 degrees C followed a kinetic equation, and the grain growth exponent varied with temperature. The activation energy values indicated that bulk diffusion was the main grain growth mechanism. The alloy exhibited excellent thermal stability below 500 degrees C and the microstructure evolution was influenced by the dissolution of the long-period stacking ordered phase.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Ceramics
Nicholas L. Clark, Shih-Yi Chuang, John C. Mauro
Summary: The study shows that the dynamics in glasses with nanoscale phase separation transition from LSW-type to a diffusion-controlled pseudo-coalescence mechanism at about 17% droplet volume fraction, leading to elongation and interconnection of droplets. Calcium diffusion is suggested to be the main cause for the coarsening of silica-rich domains, and the transition cannot be explained by Brownian motion or Van der Waals attraction, indicating various osmotic forces may be at play.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
S. L. Semiatin, J. S. Tiley, F. Zhang, T. M. Smith, R. Y. Zhang, H. B. Dong, P. Gadaud, J. Cormier
Summary: A fast-acting mean-field method for simulating precipitation of gamma '' and gamma ' phases in superalloy 718 aging process has been developed and validated through literature observations. The approach includes corrections for non-spherical shapes of precipitates, particularly for gamma '', and emphasizes the importance of selecting input material properties. Simulation results show good agreement with experimental measurements in terms of precipitate volume fraction and average size evolution, with the sensitivity of model predictions to input parameters quantified.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Hui-Hu Lu, Hong-Kui Guo, Wei Liang
Summary: In this study, a dissolution heat treatment was applied to restore the plasticity of embrittled superferritic stainless steel caused by the precipitation of sigma-phase, chi-phase, and Laves phase. The dissolution behavior of the brittle precipitation phases, as well as their effects on the mechanical properties, were investigated. It was observed that the plasticity of the tested steels was recovered after dissolution treatment, and the fracture mode changed from brittle to toughness.
MATERIALS CHARACTERIZATION
(2022)
Article
Chemistry, Physical
G. Greenidge, S. Price, J. Erlebacher
Summary: The structural transformations of carbon were studied through melt spinning and subsequent annealing of nickel-carbon alloys, revealing the ability to fine-tune the microstructure by controlling carbon content and annealing temperature. The study demonstrated the precipitation of carbon from nickel lattice on ribbon surfaces and the formation of spherical precipitates within the nickel matrix, showing potential for tailored material properties through controlled processing parameters.
Article
Mathematics, Applied
Giulio Lauretano, Renato Spigler
Summary: The study compares the Lifshitz-Slyozov (LS) and the Lifshitz-Slyozov-Wagner (LSW) models, discussing the non-monotonic behavior of monomers' concentration and theoretically justifying the approximation of the LSW model for the LS model using an asymptotic approach. Illustrative examples are provided.
SIAM JOURNAL ON APPLIED MATHEMATICS
(2021)
Article
Materials Science, Multidisciplinary
Zhengyan Zhang, Zhenqiang Wang, Zhaodong Li, Xinjun Sun
Summary: The microstructure and precipitation behaviors of Nb and Nb-Mo microalloyed fire-resistant steels were investigated before and after tension at elevated temperature. It was found that the martensite and austenite islands disappeared after tempering, and nanometer-sized carbide precipitated. The precipitation of Nb increased in Nb-Mo steel after tempering, indicating that Mo promotes the precipitation of Nb.
Article
Polymer Science
Jun Zhong, Xinyue Zhang, Xiaofeng Yu, Xuanyu Shi, Shihao Sun, Li Yang, Min Zuo, Yihu Song, Qiang Zheng
Summary: The selective distribution of silica nanoparticles grafted with crosslinked PMMA in PMMA/SAN blend was studied. Highly crosslinked PMMA chains mainly located in the PMMA-rich domains, while linear PMMA chains mainly located at the blend matrix interface. NPs grafted with slightly crosslinked chains were partially located at the interface and partially in the PMMA-rich domains. The deviation between theoretical prediction and actual location of modified NPs may be related to the heterogeneity of miniemulsion polymerization. The different locations of modified NPs induced by different grafted chain structures can result in various compatibilization effects on PMMA/SAN blend.
Article
Chemistry, Physical
Abhishek K. K. Sharma, Fernando A. A. Escobedo
Summary: Monte Carlo simulations were used to investigate the effects of particle aspect ratio on the kinetics and phase behavior of hard gyrobifastigia (GBF). The results showed that an increase in aspect ratio reduces the kinetic barrier for the isotropic-crystal transition and stabilizes an intermediate nematic phase for highly oblate and prolate ratios. The study also supported two conjectures for crystallization: low phase free energies at the ordering phase transition correlate with low transition barriers, and the emergence of a mesophase expedites crystallization.
JOURNAL OF CHEMICAL PHYSICS
(2023)
