Transformation Kinetics and Resulting Microstructure in MMC Reinforced with TiC Particles

2011 ◽  
Vol 172-174 ◽  
pp. 747-752 ◽  
Author(s):  
Mickael Mourot ◽  
Alice Courleux ◽  
Moukrane Dehmas ◽  
Elisabeth Aeby-Gautier ◽  
Guillaume Geandier ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Chemical Composition ◽  
Chemical Reactivity ◽  
Atom Probe ◽  
Steel Matrix ◽  
Transformation Kinetics ◽  
Consolidation Process ◽  
Phase Transformation Kinetics ◽  
The Matrix ◽  
Complementary Techniques

The phase transformation kinetics on cooling and resulting microstructures of steel-based matrix composites (MMC) reinforced with TiC particles by powder metallurgy were studied. In addition, the phase transformation kinetics of the MMC were compared to those of the same steel without TiC and consolidated in the same conditions. The presence of TiC particles strongly favors the diffusive transformations in the steel matrix of the MMC. Different complementary techniques (XRD, SEM, TEM/EDX, atom probe tomography, in situ synchrotron XRD) were performed to analyze the chemical reactivity between TiC particles and the steel powders occurring during consolidation process and further heat treatments. Composition changes in the TiC as well as in the matrix were characterized. The chemical composition after treatment in the TiC particles tends toward the thermodynamic calculations with ThermoCalc. The effect of changes in chemical composition and the role of TiC particles acting as new favorable nucleation sites are discussed in regards to the obtained results.

scholarly journals Continuous Cooling Transformation Behaviour and Bainite Transformation Kinetics of 23CrNi3Mo Carburised Steel

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 48
Author(s):  
Wenjun Song ◽  
Min Lei ◽  
Mingpan Wan ◽  
Chaowen Huang
Keyword(s):  
Phase Transformation ◽  
Volume Fraction ◽  
Austenite Formation ◽  
Steel Matrix ◽  
Transformation Kinetics ◽  
Bainite Transformation ◽  
Continuous Cooling ◽  
The Matrix ◽  
Dimensional Growth ◽  
Kinetics Of

In this study, the phase transformation behaviour of the carburised layer and the matrix of 23CrNi3Mo steel was comparatively investigated by constructing continuous cooling transformation (CCT) diagram, determining the volume fraction of retained austenite (RA) and plotting dilatometric curves. The results indicated that Austenite formation start temperature (Ac1) and Austenite formation finish temperature (Ac3) of the carburised layer decreased compared to the matrix, and the critical cooling rate (0.05 °C/s) of martensite transformation is significantly lower than that (0.8 °C/s) of the matrix. The main products of phase transformation in both the carburised layer and the matrix were martensite and bainite microstructures. Moreover, an increase in carbon content resulted in the formation of lamellar martensite in the carburised layer, whereas the martensite in the matrix was still lath. Furthermore, the volume fraction of RA in the carburised layer was higher than that in the matrix. Moreover, the bainite transformation kinetics of the 23CrNi3Mo steel matrix during the continuous cooling process indicated that the mian mechanism of bainite transformation of the 23CrNi3Mo steel matrix is two-dimensional growth and one-dimensional growth.

scholarly journals Solid state phase transformation kinetics in Zr-base alloys

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. R. Massih ◽  
Lars O. Jernkvist
Keyword(s):  
Phase Transformation ◽  
Solid State ◽  
Zirconium Alloys ◽  
Excess Oxygen ◽  
Transformation Kinetics ◽  
Fuel Cladding ◽  
Reactor Accident ◽  
Phase Transformation Kinetics ◽  
Solid State Phase Transformation ◽  
Water Reactors

AbstractWe present a kinetic model for solid state phase transformation ($$\alpha \rightleftharpoons \beta$$ α ⇌ β ) of common zirconium alloys used as fuel cladding material in light water reactors. The model computes the relative amounts of $$\beta$$ β or $$\alpha$$ α phase fraction as a function of time or temperature in the alloys. The model accounts for the influence of excess oxygen (due to oxidation) and hydrogen concentration (due to hydrogen pickup) on phase transformation kinetics. Two variants of the model denoted by A and B are presented. Model A is suitable for simulation of laboratory experiments in which the heating/cooling rate is constant and is prescribed. Model B is more generic. We compare the results of our model computations, for both A and B variants, with accessible experimental data reported in the literature covering heating/cooling rates of up to 100 K/s. The results of our comparison are satisfactory, especially for model A. Our model B is intended for implementation in fuel rod behavior computer programs, applicable to a reactor accident situation, in which the Zr-based fuel cladding may go through $$\alpha \rightleftharpoons \beta$$ α ⇌ β phase transformation.

scholarly journals A study on the effect of the number of clusters at the phase transformation kinetics

2021 ◽  
Author(s):  
Nathan Fernandes Ignácio ◽  
Maisa Silva Fernandes ◽  
Diego Magalhães Baía ◽  
Ana Gabriela Conceição dos Santos ◽  
Felipe da Silva Siqueira ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Transformation Kinetics ◽  
Number Of Clusters ◽  
Phase Transformation Kinetics

scholarly journals Phase transformation kinetics of zirconium under ramp wave loading with different windows

2018 ◽  
Vol 67 (7) ◽  
pp. 070204
Author(s):  
Chong Tao ◽  
Wang Gui-Ji ◽  
Tan Fu-Li ◽  
Zhao Jian-Heng ◽  
Tang Zhi-Ping
Keyword(s):  
Phase Transformation ◽  
Wave Loading ◽  
Transformation Kinetics ◽  
Phase Transformation Kinetics ◽  
Kinetics Of

Nb-H Thin Films: On Phase Transformation Kinetics

2017 ◽  
Vol 371 ◽  
pp. 160-165
Author(s):  
Vladimir Burlaka ◽  
Kai Nörthemann ◽  
Astrid Pundt
Keyword(s):  
Thin Films ◽  
Phase Transformation ◽  
Scanning Tunneling ◽  
State Change ◽  
Transformation Kinetics ◽  
Tunneling Microscopy ◽  
Fast Phase ◽  
Phase Transformation Kinetics ◽  
Local Lattice ◽  
The Impact

It was recently shown that phases forming in thin films undergo a coherency state change depending on the film thickness. For Nb-H thin films, the coherency state was reported to change at about 38 nm. In this study the impact of the coherency state on the phase transformation kinetics is investigated for Nb films of two different film thicknesses (25 nm and 80 nm), below and above the state change thickness. The phase transformation in thin metal-hydrogen films can be studied by surface topography analyses via scanning tunneling microscopy (STM) because of the strong local lattice expansion of the hydride precipitates. STM on Nb-H reveals fast phase transformation kinetics for the 25 nm Nb-film, and much slower kinetics for the 80 nm film. This is suggested to be related to the change in the coherency between the Nb-matrix and the hydride precipitates.

Phase transformation kinetics during continuous heating of a β-quenched Ti–10V–2Fe–3Al alloy

2014 ◽  
Vol 50 (3) ◽  
pp. 1412-1426 ◽  
Author(s):  
Pere Barriobero-Vila ◽  
Guillermo Requena ◽  
Fernando Warchomicka ◽  
Andreas Stark ◽  
Norbert Schell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Continuous Heating ◽  
Transformation Kinetics ◽  
Phase Transformation Kinetics
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