scholarly journals An Atom Probe Study of Kappa Carbide Precipitation and the Effect of Silicon Addition

2014 ◽  
Vol 45 (5) ◽  
pp. 2421-2435 ◽  
Author(s):  
Laura N. Bartlett ◽  
David C. Van Aken ◽  
Julia Medvedeva ◽  
Dieter Isheim ◽  
Nadezhda I. Medvedeva ◽  
...  
Keyword(s):  
Atom Probe ◽  
Carbide Precipitation ◽  
Silicon Addition ◽  
Kappa Carbide

Atom probe and STEM studies of carbide precipitation in 2Cr1Mo steel

1993 ◽  
Vol 67 (1-4) ◽  
pp. 334-341 ◽  
Author(s):  
R.C. Thomson ◽  
H.K.D.H. Bhadeshia
Keyword(s):  
Atom Probe ◽  
Carbide Precipitation

scholarly journals Evolution of Microstructure during Isothermal Treatments of a Duplex-Austenitic 0.66C11.4Mn.9.9Al Low-Density Forging Steel and Effect on the Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 214
Author(s):  
Idurre Kaltzakorta ◽  
Teresa Gutierrez ◽  
Roberto Elvira ◽  
Pello Jimbert ◽  
Teresa Guraya
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Strength ◽  
Grain Boundaries ◽  
Automotive Industry ◽  
Carbide Precipitation ◽  
Water Quenching ◽  
Low Density ◽  
Evolution Of Microstructure ◽  
Kappa Carbide

In the last decades, low-density steels for forging have increasing interest in the automotive industry, and good mechanical properties are required for their real application. This paper describes the results obtained for a 0.66C11.4Mn9.9Al duplex austenitic low-density steel after applying a set of isothermal treatments at different combinations of time and temperature, aimed to promote kappa carbide precipitation, and improve the mechanical properties obtained with a water quenching treatment. The effects of the different isothermal treatments on the microstructure and on the mechanical properties have been analyzed and compared to those obtained from a quenching heat treatment. We found that isothermal treatments in the range temperature between 550–750 °C promoted the profuse precipitation of coarse kappa carbides at grain boundaries, which dramatically reduced the ductility of the alloy, whereas a traditional quenching treatment resulted in a better combination of ductility and mechanical strength.

Microstructural Features of 'Quenching and Partitioning': A New Martensitic Steel Heat Treatment

2007 ◽  
Vol 539-543 ◽  
pp. 4819-4825 ◽  
Author(s):  
D.V. Edmonds ◽  
K. He ◽  
Michael K. Miller ◽  
F.C. Rizzo ◽  
A. Clarke ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Sheet Steel ◽  
Atom Probe ◽  
Carbide Precipitation ◽  
Martensite Phase ◽  
Quenching And Partitioning ◽  
Transmission Electron ◽  
Quench Temperature ◽  
Untransformed Austenite ◽  
Quenching And Tempering

The microstructure following a new martensite heat treatment has been examined, principally by high-resolution microanalytical transmission electron microscopy and by atom probe tomography. The new process involves quenching to a temperature between the martensite-start (Ms) and martensite-finish (Mf) temperatures, followed by ageing either at or above, the initial quench temperature, whereupon carbon can partition from the supersaturated martensite phase to the untransformed austenite phase. Thus the treatment has been termed ‘Quenching and Partitioning’ (Q&P). The carbon must be protected from competing reactions, primarily carbide precipitation, during the first quench and partitioning steps, thus enabling the untransformed austenite to be enriched in carbon and largely stabilised against further decomposition to martensite upon final quenching to room temperature. This microstructural objective is almost directly opposed to conventional quenching and tempering of martensite, which seeks to eliminate retained austenite and where carbon supersaturation is relieved by carbide precipitation. This study focuses upon a steel composition representative of a TRIP-assisted sheet steel. The Q&P microstructure is characterised, paying particular attention to the prospect for controlling or suppressing carbide precipitation by alloying, through examination of the carbide precipitation that occurs.

scholarly journals Carbide Precipitation in a Low Alloyed Steel during Aging Studied by Atom Probe Tomography and Thermodynamic Modeling

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2009
Author(s):  
Mattias Thuvander ◽  
Hans Magnusson ◽  
Ulrika Borggren
Keyword(s):  
Atom Probe Tomography ◽  
Precipitation Hardening ◽  
Atom Probe ◽  
Carbide Precipitation ◽  
Martensitic Structure ◽  
Number Density ◽  
High Number Density ◽  
Molybdenum Carbides ◽  
The Matrix ◽  
Low Alloyed Steel

Carbide precipitation in martensitic low alloyed steels contributes to the mechanical properties through precipitation hardening. A high number density of carbides is desired to maximize the hardening effect, which is achieved through the precipitation of carbides on the dislocations in the martensitic structure. In this study, the nucleation, growth, and coarsening of vanadium and molybdenum carbides during aging at 600 °C for periods up to four weeks were investigated. The work covers characterization with atom probe tomography, which showed that the nucleation of V and Mo rich MC/M2C carbides takes place on dislocations. The growth of these carbides proceeds by the diffusion of elements to the dislocations, which has been modeled using Dictra software, confirming the rate of the reaction as well as the depletion of carbide formers in the matrix. For longer aging times, particle coarsening will decrease the number density of particles with a transition from dislocation-based carbides to separate rounded carbides.

scholarly journals Kappa Carbide Precipitation in Duplex Fe-Al-Mn-Ni-C Low-Density Steel

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1261
Author(s):  
Jaka Burja ◽  
Barbara Šetina Batič ◽  
Tilen Balaško
Keyword(s):  
Induction Furnace ◽  
Carbide Precipitation ◽  
Vacuum Induction Furnace ◽  
Low Density ◽  
Transportation Industry ◽  
Cast State ◽  
Cast Sample ◽  
B2 Phase ◽  
Increasing Temperature ◽  
Kappa Carbide

The microstructural evolution of a Fe-Mn-Al-Ni-C low-density steel was studied. The lightweight low-density steels are a promising material for the transportation industry, due to their good mechanical properties and low density. The base microstructure of the investigated steel consists of ferrite and austenite. Thermo-Calc calculations showed the formation of an ordered BCC (body-centred cubic) B2 phase below 1181 °C and kappa carbides below 864 °C. The steel was produced in a vacuum induction furnace, cast into ingots and hot forged into bars. The forged bars were solution annealed and then isothermally annealed at 350, 450, 550, 650, 750, and 850 °C. The microstructure of the as-cast state, the hot forged state, solution annealed, and isothermally annealed were investigated by optical microscopy and scanning electron microscopy. The results showed the formation of kappa carbides and the ordered B2 phase. The kappa carbides appeared in the as-cast sample and at the grain boundaries of the isothermally annealed samples. At 550 °C, the kappa carbides began to form in the austenite phase and coarsened with increasing temperature.

scholarly journals Nanoscale Solute Partitioning and Carbide Precipitation in a Multiphase TRIP Steel Analyzed by Atom Probe Tomography

JOM ◽  
2018 ◽  
Vol 70 (9) ◽  
pp. 1752-1757 ◽  
Author(s):  
Arun Devaraj ◽  
Zeren Xu ◽  
Fadi Abu-Farha ◽  
Xin Sun ◽  
Louis G. Hector
Keyword(s):  
Atom Probe Tomography ◽  
Trip Steel ◽  
Atom Probe ◽  
Carbide Precipitation ◽  
Solute Partitioning
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