Author
M. Charleux
Bio: M. Charleux is an academic researcher from STMicroelectronics. The author has contributed to research in topics: Precipitation hardening & Microalloyed steel. The author has an hindex of 1, co-authored 1 publications receiving 193 citations.
Papers
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TL;DR: In this paper, the precipitation behavior of a commercial high-strength low-alloy (HSLA) steel microalloyed with 0.086 wt pct Nb and 0.047 wtpct Ti has been investigated using transmission electron microscopy (TEM) and mechanical testing.
Abstract: The precipitation behavior of a commercial high-strength low-alloy (HSLA) steel microalloyed with 0.086 wt pct Nb and 0.047 wt pct Ti has been investigated using transmission electron microscopy (TEM) and mechanical testing. The emphasis of this study is to compare an industrially hot-rolled steel and samples from a laboratory hot torsion machine simulation. From TEM observations, the Ti and Nb containing precipitates could be grouped according to their size and shape. The precipitates in order of size were found to be cubic TiN particles with sizes in the range of 1 µm, grain boundary precipitates with diameters of approximately 10 nm, and very fine spherical or needle-shaped precipitates with sizes on the order of 1 nm. The needlelike precipitates were found on dislocations in ferrite and constituted the dominant population in terms of density. Thus, they appear to be responsible for the precipitation strengthening observed in this steel. Aging tests were carried out at 650°C to evaluate the precipitate strengthening kinetics in detail. The strengthening mechanisms can be described with a nonlinear superposition of dislocation and precipitation hardening. The mechanical properties of torsion-simulated material and as-coiled industrial material are similar; however, there are some microstructural differences that can be attributed to the somewhat different processing routes in the laboratory as compared to hot strip rolling.
229 citations
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TL;DR: In this article, a review article summarizes the recent progresses on the complex interaction between second-phase particles and recrystallization and the science behind them, and concludes that the double-edge effect of second phase particles on the behavior and mechanical properties of metallic materials is still far from being clear.
361 citations
TL;DR: In this article, the lattice parameters, formation energies and bulk moduli of (Ti, M)C and M(C, Va) with the B1 crystal structure have been investigated using first-principles calculations, where M = Nb, V, Mo and W.
290 citations
15 Jan 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the effects of Ti, Ti-Mo, and Ti-Nb microalloy additions on the precipitation strengthening in three experimental high-strength low-alloy steels have been investigated.
Abstract: The effects of Ti, Ti–Mo, and Ti–Nb microalloy additions on the precipitation strengthening in three experimental high-strength low-alloy steels have been investigated. The objective of this work was to study the carbide precipitation under the conditions of continuous cooling and interrupted cooling. It was found that titanium molybdenum complex carbide, (Ti, Mo)C, can strongly maintain nanometer-scaled sizes and has the largest contribution to the hardness as compared to titanium carbide, TiC, and titanium niobium complex carbide, (Ti, Nb)C. The result emphasizes that (Ti, Mo)C particles possess an excellent behavior of thermal stability.
200 citations
15 Apr 2008-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a new ultra-high strength niobium-microalloyed pipeline steel of yield strength ∼700 MPa has been processed, which is derived from the cumulative combination of fine grain size, solid solution strengthening with additional interstitial hardening, precipitation hardening from carbides, dislocation hardening and mixed microstructure.
Abstract: A new ultrahigh strength niobium-microalloyed pipeline steel of yield strength ∼700 MPa has been processed. The Charpy impact toughness at 0 °C was 27 J and tensile elongation was 16%. The ultrahigh strength is derived from the cumulative combination of fine grain size, solid solution strengthening with additional interstitial hardening, precipitation hardening from carbides, dislocation hardening, and mixed microstructure. The microstructure was characterized by polygonal ferrite, upper bainite, degenerated pearlite, and martensite–austenite (MA) constituents. The microstructure of weld and heat-affected zone (HAZ) was similar to the base metal such that the hardness is retained in the weld region implying insignificant softening in the weld zone. Niobium and titanium precipitates of different morphology and size range evolved during thermomechanical processing and include rectangular (∼500 nm), irregular (∼240–500 nm), cuboidal/spherical (∼125–300 nm), and very fine (
146 citations
TL;DR: In this article, a grain growth model was developed, which includes the pinning effect of precipitates present in the steel, and an approach was developed to estimate the initial distribution of precipitate in the as-received material and their dissolution kinetics.
144 citations