Fabrication of cube-on-face textured Fe-1wt%Si and Fe-2wt%Si-1wt%Ni electrical steel using surface nucleation during γ → α phase transformation

2020 ◽  
Vol 170 ◽  
pp. 110724
Author(s):  
Yong-Keun Ahn ◽  
Soo-Bin Kwon ◽  
Yong-Kwon Jeong ◽  
Ji-Ung Cho ◽  
Tae-Young Kim ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Electrical Steel ◽  
Surface Nucleation ◽  
Α Phase

Effects of α–γ–α Phase Transformation on the ∑3 Boundaries in High-Purity Iron

2021 ◽  
Author(s):  
Syed Ejaz Hussain ◽  
Weiguo Wang ◽  
Xinfu Gu ◽  
Yunkai Cui ◽  
Ahua Du ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Purity ◽  
Α Phase ◽  
Purity Iron ◽  
High Purity Iron

scholarly journals Oxygen Induced Phase Transformation in TC21 Alloy with a Lamellar Microstructure

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 163
Author(s):  
Shu Wang ◽  
Yilong Liang ◽  
Hao Sun ◽  
Xin Feng ◽  
Chaowen Huang
Keyword(s):  
Electron Microscopy ◽  
Phase Transformation ◽  
Oxygen Uptake ◽  
Titanium Alloys ◽  
Electron Backscatter Diffraction ◽  
Lamellar Microstructure ◽  
Α Phase ◽  
Transmission Electron ◽  
The Matrix ◽  
Oxygen Ingress

The main objective of the present study was to understand the oxygen ingress in titanium alloys at high temperatures. Investigations reveal that the oxygen diffusion layer (ODL) caused by oxygen ingress significantly affects the mechanical properties of titanium alloys. In the present study, the high-temperature oxygen ingress behavior of TC21 alloy with a lamellar microstructure was investigated. Microstructural characterizations were analyzed through optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). Obtained results demonstrate that oxygen-induced phase transformation not only enhances the precipitation of secondary α-phase (αs) and forms more primary α phase (αp), but also promotes the recrystallization of the ODL. It was found that as the temperature of oxygen uptake increases, the thickness of the ODL initially increases and then decreases. The maximum depth of the ODL was obtained for the oxygen uptake temperature of 960 °C. In addition, a gradient microstructure (αp + β + βtrans)/(αp + βtrans)/(αp + β) was observed in the experiment. Meanwhile, it was also found that the hardness and dislocation density in the ODL is higher than that that of the matrix.

scholarly journals High-Performance Formamidinium-Based Perovskite Solar Cells via Microstructure-Mediated δ-to-α Phase Transformation

2017 ◽  
Vol 29 (7) ◽  
pp. 3246-3250 ◽  
Author(s):  
Tanghao Liu ◽  
Yingxia Zong ◽  
Yuanyuan Zhou ◽  
Mengjin Yang ◽  
Zhen Li ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Solar Cells ◽  
High Performance ◽  
Perovskite Solar Cells ◽  
Α Phase

scholarly journals Formation of Large Size Precipitate-Free Zones in β Annealing of the Near-β Ti-55531 Titanium Alloy

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 544 ◽  
Author(s):  
Xueqi Jiang ◽  
Xiaoqiang Shi ◽  
Xiaoguang Fan ◽  
Qi Li
Keyword(s):  
Titanium Alloy ◽  
Phase Transformation ◽  
Heterogeneous Nucleation ◽  
Isothermal Heat Treatment ◽  
Precipitate Free Zone ◽  
Mode Iii ◽  
Slow Cooling ◽  
Free Zone ◽  
Large Size ◽  
Α Phase

Large size (>10000 μm2) precipitate-free zones in the absence of microsegregation were observed in the near-β Ti-55531 titanium alloy after furnace cooling from high temperature and longtime annealing in the single-β phase field. To reveal the formation mechanism of the large size precipitate-free zone, continuous cooling and isothermal heat treatment were carried out to investigate the β-α phase transformation process. It was found that the large size precipitate free zone is attributed to the heterogeneous nucleation of α phase. The nucleation site evolves in three different modes: I-random nucleation inside the β grain, II-network nucleation inside the β grain and, III-heterogeneous nucleation on the precipitated α phase. Modes I and II lead to homogeneous transformed structure while Mode III results in the large size precipitate-free zone. Both modes II and III are promoted at high annealing temperature, rapid cooling above 600 °C or slow cooling below 600 °C. Mode II is common as it can minimize the strain energy in phase transformation. As a result, the formation of the large size precipitate-free zone is not deterministic.

Processing of silicon carbide ceramics using chemically modified polycarbosilanes

1999 ◽  
Vol 14 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Sachiko Okuzaki ◽  
Yuji Iwamoto ◽  
Shinji Kondoh ◽  
Koichi Kikuta ◽  
Shin-ichi Hirano
Keyword(s):  
Silicon Carbide ◽  
Phase Transformation ◽  
Nucleation Site ◽  
Metal Alkoxide ◽  
Transformation Behavior ◽  
Ceramic Yield ◽  
Chemically Modified ◽  
Α Phase ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics

Chemically modified polycarbosilane (PC) which contains Si–Al–C–O component, PCOAl, was synthesized using PC and aluminum triisopropoxide. Ceramic yield was greatly improved through the modification of PC with a metal alkoxide. The phase transformation behavior and microstructure development of silicon carbide (SiC) were studied on β–SiC powders coated with chemically modified PC. The β-α phase transformation of SiC was enhanced by the coating of chemically modified PC on β–SiC powder. A unique microstructure with submicron-sized plate-like grains was developed, since the fine a phase produced at low temperature served as a nucleation site for the β-α phase transformation of SiC.

Phase-Field Simulation on Phase Transformation during Creep Deformation in Type 304 Steel

2010 ◽  
Vol 654-656 ◽  
pp. 492-495
Author(s):  
Yuhki Tsukada ◽  
Atsuhiro Shiraki ◽  
Yoshinori Murata ◽  
Shigeru Takaya ◽  
Toshiyuki Koyama ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Dislocation Density ◽  
Phase Field ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
M23c6 Carbide ◽  
Phase Field Simulation ◽  
Field Simulation ◽  
Α Phase ◽  
Type 304

Phase-field simulation of phase transformation during creep in Type 304 austenitic steel is performed and simultaneous nucleation and growth of both M23C6 carbide and ferromagnetic α phases are reproduced. Nucleation events of these product phases are explicitly introduced through a probabilistic Poisson seeding process based on the classical nucleation theory. Creep dislocation energy near the carbide is integrated into the nucleation driving force for the α phase. We examine the effect of the dislocation density on precipitation of the α phase, and it is found that a small difference in the dislocation density leads to a significant change in precipitation behavior of the α phase.

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