Control of intermetallic compound layers at interface between steel and aluminum by diffusion-treatment
15 Dec 2002-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing (Elsevier)-Vol. 338, Iss: 1, pp 44-53
TL;DR: In this article, the growth mechanism, morphology and mechanical properties of Fe-Al intermetallic compound layers on the surface of carbon steel were systematically evaluated for specimens diffused at temperatures ranging from 873 to 1323 K after hot dip aluminizing.
Abstract: The toughening of Fe–Al intermetallic compound coating formed by aluminizing of carbon steel was investigated. The growth mechanism, morphology and mechanical properties of Fe–Al intermetallic compound layers on the surface of carbon steel were systematically evaluated for specimens diffused at temperatures ranging from 873 to 1323 K after hot dip aluminizing. Fe2Al5 was mainly formed on the specimen surfaces at the usual diffusion temperatures from 873 to 923 K. However, FeAl and Fe3Al layers having relatively high fracture resistance and oxidation resistance properties were preferentially formed in the specimens diffused at temperatures greater than 1273 K. The activation energies required for the growth of the FeAl and Fe3Al layers were QFeAl=180 and QFe3Al=260 kJ mol−1, respectively. It was identified that the formation and growth of Fe–Al intermetallic compound layers is controlled by the diffusion of Fe atoms into the intermetallic compound layers.
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TL;DR: In this article, the welding nugget can be considered as aluminum matrix composite, which is enhanced by dispersed sheared-off steel fragments encompassed by a thin inter-metallic layer or simply intermetallic particles.
243 citations
Cites background from "Control of intermetallic compound l..."
...Several researches have been conducted regarding the interlayer formation and growth between molten Al and solid Fe [37,40–43]....
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TL;DR: In this article, the cold metal transfer (CMT) welding-brazing process provides a potential method to join dissimilar metals, and it is feasible to join aluminum alloys-to-galvanized mild steel using CMT.
174 citations
15 Oct 2007-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the effect of the backing block on the formation of intermetallic reaction layer during laser welding of steel and aluminum alloy dissimilar materials has been investigated, and it was concluded that the thickness of the reaction layer could be suppressed by using a backing block (as a heat sink) for controlling heat flow in welding region.
Abstract: In order to suppress the formation of intermetallic reaction layer during laser welding of steel and aluminum alloy dissimilar materials, effect of backing block (heat sink) was investigated. FEM analysis as well as welding experiments with various backing blocks for controlling heat flow were performed. It was found that thickness of intermetallic reaction layer was reduced by increasing welding speed and by applying a backing block with higher thermal conductivity. FEM analysis also showed that when increasing welding speed or applying a backing block with higher thermal conductivity, molten time of aluminum alloy became shorter and predicted thickness of intermetallic reaction layer became thinner. It could be concluded that the thickness of intermetallic reaction layer could be suppressed by using a backing block (as a heat sink) for controlling heat flow in welding region. The joining strength was strongly dependent on the thickness of intermetallic reaction layer. Therefore the backing block was significantly effective for controlling heat flow and consequently for attaining good joining strength.
174 citations
TL;DR: In this article, the microstructure evolution of aluminized coatings during the hot stamping process is discussed, and an analysis of the cracking of the coating caused by the formation of brittle Fe-Al intermetallic phases and their high temperature deformation is presented.
Abstract: In the present contribution, recent developments of coatings for hot stamped steels are reviewed. The use of bare steel in the initial hot stamping technology is discussed, including the application of lubricant oils which are used as oxidation inhibitors on bare steel surfaces. The aluminized coatings are introduced, focusing on the microstructure evolution of aluminized coatings during the hot stamping process. An analysis of the cracking of the coating, caused by the formation of brittle Fe–Al intermetallic phases and their high temperature deformation, is presented. The development of a ductile aluminide coating formed during the diffusion treatment of an aluminized coating is discussed. This aluminide coating can endure both high temperature oxidation and severe plastic deformation. The recently developed galvanized and galvannealed coatings are also reviewed and the influence of the gas atmosphere during the heating cycle on the coating stability is emphasized. The solutions which have been proposed to avoid liquid Zn-induced embrittlement are analyzed. The use of Zn–Ni alloy coating, which is characterized by a higher melting temperature, is reviewed. The behavior of sol–gel hybrid coatings on hot stamped steels is discussed. The possible use of the recently developed Al–Zn alloy coatings, dual layer Zn–Al and Zn–Al–Mg coatings is also introduced. The application of Zn–Al–Mg post-process galvanizing is also discussed. In each case, all available information related to the weldability, paintability, and corrosion resistance of the coating systems is also reported. Finally, the advantages and technical challenges associated with each type of coating are reviewed.
159 citations
TL;DR: In this paper, the growth behavior in the intermetallic layer after various times of immersion in the hot-dip at 700 °C was analyzed by electron backscatter diffraction (EBSD).
Abstract: Mild steel was coated by hot-dipping in a molten aluminum bath. The growth behavior in the intermetallic layer after various times of immersion in the hot-dip at 700 °C was analyzed by electron backscatter diffraction (EBSD). The results showed that the aluminide layer consisted of an outer aluminum topcoat, minor FeAl 3 and major Fe 2 Al 5 , respectively. From another perspective, Fe 2 Al 5 possessed a tongue-like morphology, which caused the corresponding serration-like morphology of the steel substrate. The Fe-Al/steel substrate interface of the Fe 2 Al 5 phase, after removal of the steel substrate, displayed a columnar structure growing toward the steel substrate, implying that Fe 2 Al 5 grew at a rapid rate along the diffusion direction. Moreover, the EBSD results revealed the Fe 2 Al 5 phase was not only composed of columnar grains, but also possessed fine grains clustered around the peaks of the serration-like steel substrate.
148 citations
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01 Jan 1986
TL;DR: Binary Alloy Phase Diagrams, Second Edition, Plus Updates, on CD-ROM offers you the same high-quality, reliable data you'll find in the 3-volume print set published by ASM in 1990.
Abstract: Gives you access to the 4,700 atomic and weight percent graphs included in the reference set Binary Alloy Phase Diagrams, Second Edition, published by ASM in 1990 - plus updates! All the data from the 3,600-page, three-volume set, abstracts of phase diagram evaluations for 3,000 binary alloy systems, special points and crystal structure tables, along with 300 recent updates from the current literature are included on one CD-ROM for ease of use and storage. Binary Alloy Phase Diagrams plus updates on CD-ROM containing all the data from Massalski's world standard, three-volume, 3,600-page Binary Alloy Phase Diagrams, Second Edition, fits in the palm of your hand! This CD includes 4,700 diagrams; abstracts of phase diagram evaluations for 3,000 binary alloy systems; special points; crystal structure tables; plus 300 recent updates from current literature. All in databases and in CD-ROM format, so it's easier to access, more flexible to use, and more efficient for you to store than ever before. Binary Alloy Phase Diagrams, Second Edition, Plus Updates, on CD-ROM, offers you the same high-quality, reliable data you'll find in the 3-volume print set published by ASM in 1990. The over 4,700 diagrams were digitized from original program graphs or redrawn from carefully selected data sources. Each diagram is in accordance to thermodynamic principles and is consistent with melting and phase-transition temperatures of the pure elements. All diagrams met strict quality standards throughout preparation. Now, the CD-ROM format puts this quality information at your fingertips. These are not scanned pages, but true, complete databases of phase diagram and crystallographic information, all in one incredibly small but powerful package, you'll wonder what you ever did without it! This new electronic format allows you to: Search for diagrams, crystal structure data, or text by keying in the alloys. Search the Master Crystal Structure Table for Intermetallic compounds with equivalent structure type, temperature, and phase width criteria. Print diagrams, text, crystal structure. Examine any new data in conjunction with the original data as presented in the print volume. Zoom in on a complicated section of the diagram for a closer look. (Vat payable on UK orders for CD products) Multi-User prices available: Contact Steve French (Customer Services Manager) Telephone: +44 (0)1462 437933; E-Mail: SFrench@ameritech.co.uk
13,433 citations
TL;DR: In this paper, the authors summarize recent developments concerning Fe3Al-based aluminides, including alloy development efforts and environmental embrittlement studies, and review studies of fabrication, mechanical properties, and corrosion resistance that have been conducted since that time.
Abstract: Fe3Al-based iron aluminides have been of interest for many years because of their excellent oxidation and sulfidation resistance. However, limited room temperature ductility (<5%) and a sharp drop in strength above 600 °C have limited their consideration for use as structural materials. Recent improvements in tensile properties, especially improvements in ductility produced through control of composition and microstructure, and advances in the understanding of environmental embrittlement in intermetallics, including iron aluminides, have resulted in renewed interest in this system for structural applications. The purpose of this paper is to summarize recent developments concerning Fe3Al-based aluminides, including alloy development efforts and environmental embrittlement studies. This report will concentrate on literature published since about 1980, and will review studies of fabrication, mechanical properties, and corrosion resistance that have been conducted since that time.
643 citations
01 Dec 1998-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: A broad survey of the physical, mechanical and corrosion properties of Fe3Al alloys, as well as a review of principal processing methods is presented in this paper, where the influence of alloying elements on corrosion and stress corrosion resistance and weldability also is reviewed.
Abstract: This paper constitutes a broad survey of the physical, mechanical and corrosion properties of Fe3Al alloys, as well as a review of principal processing methods. This class of alloys, once thought to be inherently brittle, is shown to possess moderate ductility, provided that mechanical testing is carried out in an inert environment. Methods to improve mechanical properties by alloying and microstructural control are described. The influence of alloying elements on corrosion and stress corrosion resistance and weldability also is reviewed.
465 citations
30 Jun 1998-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the interaction between solid iron and liquid aluminium is studied by immersion tests and the intermetallic layers formed at the solid-liquid interface and their growth mechanisms are characterized.
Abstract: The interaction between solid iron and liquid aluminium is studied by immersion tests. At first, the intermetallic layers formed at the solid–liquid interface and their growth mechanisms are characterized. The Fe 2 Al 5 and FeAl 3 phases are identified in the temperature range from 700 to 900°C, and their growth is found to be mainly controlled by a diffusion regime. Then, a theoretical approach of the phase growth based on the solutions of the diffusion equations is presented. Theory and experiment agree rather well.
358 citations
TL;DR: Using both a parabolic law for crystal growth and an exponential law for dissolution of solids in liquids, an equation describing the diffusion-controlled growth of a single-phase intermetallic layer has been derived as discussed by the authors.
Abstract: Using both a parabolic law for crystal growth and an exponential law for dissolution of solids in liquids, an equation describing the diffusion-controlled growth of a single-phase intermetallic layer has been derived. This equation enables calculation of the interlayer thickness as a function of time under given conditions of interaction of a solid metal with a liquid one. The growth rate of the Fe2Al5 interlayer follows the predicted time dependence.
134 citations