Metallurgical Research & Technology 2014 Best Paper Award (February 2015)
We are delighted to announce the winner of the Metallurgical Research & Technology 2014 Best Paper Award.
The Metallurgical Research & Technology Best Paper Award honors the author(s) of a paper of exceptional merit dealing with research and/or industrial aspects in metallurgy and bringing an outstanding contribution to the field.
All articles published during the current year prior to the award, including Short Communications, Regular articles, Reviews and Topical issue papers, can be considered for an award. The papers are judged in December each year using the criteria of originality, innovation, significance to the research community, industrial relevance, technical excellence, impact, and clarity of presentation. The authors of the awarded articles will receive a book that they choose from the EDP Sciences catalogue in addition they will be given the possibility to publish on the journal website, a news article about their work or their laboratory/team.
First prize winners
David Zapico Álvarez, Florence Bertrand, Jean-Michel Mataigne and Marie-Laurence Giorgi for their article "Nature of the inhibition layer in GA baths", published in volume 111/1, 2014, p 9. The Editorial board of Metallurgical Research & technology underlines the scientific and industrial importance of the study presented in the article in the fields of hot-dipping, solid/liquid interface, intermetallic compounds, inhibition layer and galvannealed coating.
About the article
The nature of the intermetallic layer which forms on the steel surface during immersion in typical galvanizing baths for galvannealed (GA) sheets production is the subject of intense controversy for many years. Most of the authors claim the presence of Fe2Al5Znx solely, similarly to what is observed with Al richer baths used for the production of regular galvanized sheets.
This work solves this issue by showing that GA inhibition layers are biphasic and made of a very thin Fe2Al5Znx, getting discontinuous as the bath Al content decreases, covered by a thicker and continuous Al saturated Zn-Fe phase, as predicted by thermodynamic analysis of the reaction. Such knowledge allows an improved bath chemical composition control thanks to the possibility of precise calculation of the real Al consumption rate during production.
About the authors
David Zapico Álvarez, born in 1984, got his master degree in Chemical Engineering from University of Oviedo (Spain) in 2010 after completing a one-year exchange in the Institut National Polytechnique de Toulouse in 2008-2009. He started his PhD on galvannealing reaction with ArcelorMittal and Ecole Centrale Paris in March 2011 and completed it in February 2014. He conducted his work within the “Surfaces & Coatings” cluster of the Automotive Products Centre of ArcelorMittal Global R&D, located in Maizières-les-Metz, France. Presently, he belongs to that team as a researcher and is involved in the development of galvanized third generation high strength steels.
David’s work was coached by Florence Bertrand, born in 1966. She completed a master degree in engineering at INSA-Lyon then joined IRSID, the former shared research centre of the French steel industry in 1990. She started her career by studying steel making process, and then she joined, seven years later, the research team involved in continuous galvanizing. She studied gas-metal reactions occurring during continuous annealing prior to hot dip galvanizing and so contributed to the development of galvanized TRIP steels. Next, she joined the Automotive Products Centre and conducted research work leading to the development of the Ultragal® coating, a galvanized coating exhibiting an improved appearance after stamping and painting. For a few years now, she is involved in modelling the galvannealing reaction kinetic, making use of thermodynamic analysis and diffusion laws.
Marie-Laurence Giorgi, born in 1972, Professor at École Centrale Paris, directed David’s PhD work. Her PhD, completed in 2000, gives a physical model of the nucleation and growth of the Fe2Al5Znx inhibition layer that appears at immersion in the continuous hot dip galvanizing process. She joined ECP after completion of her PhD and developed there a sessile drop equipment allowing the study of wetting of solid surfaces by metallic liquids. She leaded numerous PhD works on the interactions between solid and liquid metals, some of them in collaboration with ArcelorMittal.
Jean-Michel Mataigne, born in 1960, played the role of scientific mentor for David during his PhD. Jean-Michel got an engineering degree in Applied Physics from UCL Louvain-la-Neuve (Belgium) in 1985. He started his career at CRM, in Liège. He conducted research on gas-metal reactions occurring during batch and continuous annealing of steel sheets. He joined the research Centre of Sollac in Montataire (France) in 1992 to take the lead of the metallic coating team. He contributed to the development of Extragal®, Ultragal® and some other coatings for his company. Since 2002, he is senior researcher in the Automotive Products Centre and acts as a scientific expert in metallic coatings for ArcelorMittal.
Second prize winners (exaequo)
1. Sergiy V. Merzlikin, M. Wildau, K. Steinhoff and A.W. Hassel for their article “Prove of hydrogen formation through direct potential measurements in the rolling slit during cold rolling”, volume 111/1, 2014, p25.
About the article
Hydrogen formation and absorption on the surface of the working rolls during cold rolling often leads to hydrogen induced failure. In this work, direct potential measurements during cold rolling of zinc and X20Cr13 stainless steel were carried out in the rolling slit to follow the tribologic and galvanic mechanisms oh this phenomenon. It has been shown, that potential shift into either negative or positive direction of the rolls-product system delivers information on the processes taking place at the surface in the course of the friction, where the destruction and repassivation of the surface structures during continuous cold rolling follow each other, accompanied with intensive hydrogen evolution. Galvanic coupling of the working rolls with the product significantly intensifies the hydrogen embrittlement related problems of the rolls. As a result, atomic hydrogen is adsorbed on the surface and exhibits a pressure supported absorption into the rolls leading to failure.
About the authors
2. Bernard Monasse, Christophe Pradille and Yvan Chastel for their article “A Molecular Dynamics Simulation study of semi-solid state Fe: high temperature elasticity and void formation in liquid”, volume111/5, 2014, p283.
About the article
The present molecular dynamics model explores the high temperature semi-solid properties of iron: elastic tensor, cavitation in the melt and near a solidifying crystal front. The objective is to explore possible mechanisms initiating high temperature cracks during the last steps of solidification inside dendrite structure. The elastic constants of a perfect crystal are impressively high compared to room temperature properties. A two steps mechanism of cavitation in the melt is predicted near the growing crystal at a lower depression than in the melt. The cavitation should preferentially be initiated near the crystal surface, i.e. heterogeneous nucleation. During the pressure decrease the crystal progressively melts and quickly recrystallizes during the growth of the void cavity. This thermodynamics effect implies a transient melting/recrystallization process of dendrites which can weaken the dendrite structure and induces a crack.
Bernard Monasse is involved in molecular dynamics simulations, in crystallization processes during materials processing and in the resulting mechanical and physical properties. His work balances experimental and simulation approaches. Our molecular dynamics simulations highlight the effect of cavitation is semi-crystalline polymers, in semi-solid metals under stress and are able to predict the first step of cellulose fibrils formation during vegetable growth.
Christophe Pradille’s PhD in Materials Science and Engineering was done in Cemef, Mines-Paristech. The aim of his project contributes to understanding of hot tears phenomena. The rheological parameters and hot tear criteria were deduced from casting experiments and implemented in casting software. The molecular dynamics simulations were done to check the parameters acting on cavitation and then on cracks. After this PhD, he has created a business on material characterization.
Yvan Chastel has worked for 25 years in materials science, investigating interactions between evolutions of microstructure and thermo-mechanical characteristics, often in large strain and under complex loading. This requires to develop approaches and models coupling physics, chemistry and mechanics, at different lengthscales, from atomic scales to macroscopic boundary value problems, with transition models of volume elements at grain, phase or semi-crystalline ensembles.