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Special Issue "Intermetallic Alloys: Fabrication, Properties and Applications"

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (20 February 2015)

Special Issue Editors

Guest Editor
Dr. Marco Salerno

IIT – Italian Institute of Technology, Nanophysics Department, 16163 Genova Italy
Website | E-Mail
Interests: dental materials; atomic force microscopy; anodic porous alumina; composites; nanoindentation; surface treatment of dental implants; nanoporous oxides of valve metals
Guest Editor
Dr. Wojciech Stepniowski

Department of Advanced Materials and Technologies, Faculty of Advanced Technology and Chemistry, Military University of Technology, Kaliskiego 2 Str., 00-908 Warszawa, Poland
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Guest Editor
Dr. Jude Mary Runge

3750 North Lake Shore Drive, 7H Chicago, Illinois, 60613 USA
Website | E-Mail

Special Issue Information

Dear Colleagues,

By intermetallic compounds (intermetallics) we mean all the solid-state materials involving metallic phases. As such, we do not only consider the materials with different metallic elements ordered at different sites of a crystal lattice with defined stoichiometry and complex unit cells. Additionally, alloys, with metallic elements substituting randomly in the crystal, forming a homogeneous solid solution with different compositions, are considered as well.

Altogether, the materials in this broad class may exhibit remarkable properties, such as high melting point and hardness or high temperature resistance, excellent resistance against electrochemical and chemical corrosion, sometimes representing a compromise between ceramics and metals. Intermetallics can also have special magnetic, superconduction and chemical properties, due to their strong internal order and mixed bonding. As a consequence, intermetallics have found use in several different applications, such as magnetic and hydrogen storage materials, or in the industries of automotive and aerospace, biomedical devices and robotics. Turbine blades or dental amalgams are still examples of the use of intermetallic alloys.

The properties of intermetallics are often obtained at a cost in terms of ease of manufacturing. The present special issue addresses all the possible aspects of either fabrication, processing, characterization, and application of intermetallics. Both fundamental science and engineering aspects will be welcome as the subject of the submitted manuscripts. Similarly, both theoretical and experimental work addressing the relationship between properties and structure of intermetallic materials at all length scales will be within the scope. The various topics will include, but will not be limited to, intermetallics design, modeling and simulation, advances in processing and modification, as well as cases of successful applications in the disparate areas pointed out above.

In conclusion, it is my pleasure to invite all researchers from the community of intermetallics to submit a manuscript in the field for this special issue. Full papers, communications, and reviews are all welcome.

Marco Salerno
Wojciech Stepniowski
Jude Mary Runge
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1500 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


Keywords

 

  • intermetallic compounds
  • alloys
  • design, modeling and simulation
  • manufacturing technologies
  • processing and modification
  • corrosion resistance
  • mechanical and electrochemical properties
  • automotive and aerospace
  • biomedical applications

Published Papers (9 papers)

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Research

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Open AccessArticle Structure Determination of Au on Pt(111) Surface: LEED, STM and DFT Study
Materials 2015, 8(6), 2935-2952; doi:10.3390/ma8062935
Received: 20 January 2015 / Accepted: 8 May 2015 / Published: 27 May 2015
Cited by 14 | PDF Full-text (2339 KB) | HTML Full-text | XML Full-text
Abstract
Low-energy electron diffraction (LEED), scanning tunneling microscopy (STM) and density functional theory (DFT) calculations have been used to investigate the atomic and electronic structure of gold deposited (between 0.8 and 1.0 monolayer) on the Pt(111) face in ultrahigh vacuum at room temperature. The
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Low-energy electron diffraction (LEED), scanning tunneling microscopy (STM) and density functional theory (DFT) calculations have been used to investigate the atomic and electronic structure of gold deposited (between 0.8 and 1.0 monolayer) on the Pt(111) face in ultrahigh vacuum at room temperature. The analysis of LEED and STM measurements indicates two-dimensional growth of the first Au monolayer. Change of the measured surface lattice constant equal to 2.80 Å after Au adsorption was not observed. Based on DFT, the distance between the nearest atoms in the case of bare Pt(111) and Au/Pt(111) surface is equal to 2.83 Å, which gives 1% difference in comparison with STM values. The first and second interlayer spacing of the clean Pt(111) surface are expanded by +0.87% and contracted by −0.43%, respectively. The adsorption energy of the Au atom on the Pt(111) surface is dependent on the adsorption position, and there is a preference for a hollow fcc site. For the Au/Pt(111) surface, the top interlayer spacing is expanded by +2.16% with respect to the ideal bulk value. Changes in the electronic properties of the Au/Pt(111) system below the Fermi level connected to the interaction of Au atoms with Pt(111) surface are observed. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)
Open AccessArticle Synthesis of Fe-Al-Ti Based Intermetallics with the Use of Laser Engineered Net Shaping (LENS)
Materials 2015, 8(5), 2311-2331; doi:10.3390/ma8052311
Received: 20 December 2014 / Revised: 14 April 2015 / Accepted: 17 April 2015 / Published: 29 April 2015
Cited by 1 | PDF Full-text (7948 KB) | HTML Full-text | XML Full-text
Abstract
The Laser Engineered Net Shaping (LENS) technique was combined with direct synthesis to fabricate L21-ordered Fe-Al-Ti based intermetallic alloys. It was found that ternary Fe-Al-Ti alloys can be synthesized using the LENS technique from a feedstock composed of a pre-alloyed Fe-Al
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The Laser Engineered Net Shaping (LENS) technique was combined with direct synthesis to fabricate L21-ordered Fe-Al-Ti based intermetallic alloys. It was found that ternary Fe-Al-Ti alloys can be synthesized using the LENS technique from a feedstock composed of a pre-alloyed Fe-Al powder and elemental Ti powder. The obtained average compositions of the ternary alloys after the laser deposition and subsequent annealing were quite close to the nominal compositions, but the distributions of the elements in the annealed samples recorded over a large area were inhomogeneous. No traces of pure Ti were observed in the deposited alloys. Macroscopic cracking and porosity were observed in all investigated alloys. The amount of porosity in the samples was less than 1.2 vol. %. It seems that the porosity originates from the porous pre-alloyed Fe-Al powders. Single-phase (L21), two-phase (L21-C14) and multiphase (L21-A2-C14) Fe-Al-Ti intermetallic alloys were obtained from the direct laser synthesis and annealing process. The most prominent feature of the ternary Fe-Al-Ti intermetallics synthesized by the LENS method is their fine-grained structure. The grain size is in the range of 3–5 μm, indicating grain refinement effect through the highly rapid cooling of the LENS process. The Fe-Al-Ti alloys synthesized by LENS and annealed at 1000 °C in the single-phase B2 region were prone to an essential grain growth. In contrast, the alloys annealed at 1000 °C in the two-phase L21-C14 region exhibited almost constant grain size values after the high-temperature annealing. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)
Figures

Open AccessArticle Fabrication of Fe-Al Intermetallic Foams via Organic Compounds Assisted Sintering
Materials 2015, 8(5), 2217-2226; doi:10.3390/ma8052217
Received: 17 January 2015 / Revised: 20 April 2015 / Accepted: 23 April 2015 / Published: 28 April 2015
Cited by 6 | PDF Full-text (4106 KB) | HTML Full-text | XML Full-text
Abstract
The influence of the addition of organic compounds, such as palmitic acid and cholesteryl myristate, on the porous structure of Fe-Al intermetallics formation has been investigated in detail in this paper. It was found that additives have a significant effect on the final
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The influence of the addition of organic compounds, such as palmitic acid and cholesteryl myristate, on the porous structure of Fe-Al intermetallics formation has been investigated in detail in this paper. It was found that additives have a significant effect on the final porosity of the obtained sinters. Formed gaseous products from combustion play the role of the foaming agent during Fe-Al intermetallic alloy sintering. The influence of these additives is also clearly noticeable in chemical composition changes of the final products through the increase of carbon content in the porous structure. This is attributed to the thermal decomposition, namely combustion, of the organic additives. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)
Open AccessArticle The Effect of Oxygen Partial Pressure on Microstructure and Properties of Fe40Al Alloy Sintered under Vacuum
Materials 2015, 8(4), 1513-1525; doi:10.3390/ma8041513
Received: 18 February 2015 / Revised: 18 March 2015 / Accepted: 19 March 2015 / Published: 31 March 2015
Cited by 1 | PDF Full-text (4834 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents the results of studies on the influence of oxygen partial pressure (vacuum level in the chamber) on the properties of FeAl intermetallics. One of the problems in the application of classical methods of prepared Fe-Al intermetallic is the occurrence of
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This paper presents the results of studies on the influence of oxygen partial pressure (vacuum level in the chamber) on the properties of FeAl intermetallics. One of the problems in the application of classical methods of prepared Fe-Al intermetallic is the occurrence of oxides. Applying a vacuum during sintering should reduce this effect. In order to analyze the effect of oxygen partial pressure on sample properties, five samples were processed (by a pressure-assisted induction sintering—PAIS method) under the following pressures: 3, 8, 30, 80, and 300 mbar (corresponding to oxygen partial pressures of 0.63, 1.68, 6.3, 16.8, and 63 mbar, respectively). The chemical and phase composition, hardness, density, and microstructure observations indicate that applying a vacuum significantly impacts intermetallic samples. The compact sintered at pressure 3 mbar is characterized by the most homogeneous microstructure, the highest density, high hardness, and nearly homogeneous chemical composition. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)
Open AccessArticle High-Temperature Oxidation of Fe3Al Intermetallic Alloy Prepared by Additive Manufacturing LENS
Materials 2015, 8(4), 1499-1512; doi:10.3390/ma8041499
Received: 15 January 2015 / Revised: 9 March 2015 / Accepted: 19 March 2015 / Published: 30 March 2015
Cited by 4 | PDF Full-text (3636 KB) | HTML Full-text | XML Full-text
Abstract
The isothermal oxidation of Fe-28Al-5Cr (at%) intermetallic alloy microalloyed with Zr and B (<0.08 at%) in air atmosphere, in the temperature range of 1000 to 1200 °C, was studied. The investigation was carried out on the thin-walled (<1 mm) elements prepared by Laser
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The isothermal oxidation of Fe-28Al-5Cr (at%) intermetallic alloy microalloyed with Zr and B (<0.08 at%) in air atmosphere, in the temperature range of 1000 to 1200 °C, was studied. The investigation was carried out on the thin-walled (<1 mm) elements prepared by Laser Engineered Net Shaping (LENS) from alloy powder of a given composition. Characterization of the specimens, after the oxidation, was conducted using X-ray diffraction (XRD) and scanning electron microscopy (SEM, with back-scatter detector (BSE) and energy-dispersive X-ray spectroscopy (EDS) attachments). The investigation has shown, that the oxidized samples were covered with a thin, homogeneous α-Al2O3 oxide layers. The intensity of their growth indicates that the material lost its resistance to oxidation at 1200 °C. Structural analysis of the thin-walled components’ has not shown intensification of the oxidation process at the joints of additive layers. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)
Figures

Open AccessArticle Corrosion Behavior of Detonation Gun Sprayed Fe-Al Type Intermetallic Coating
Materials 2015, 8(3), 1108-1123; doi:10.3390/ma8031108
Received: 20 December 2014 / Revised: 6 March 2015 / Accepted: 9 March 2015 / Published: 13 March 2015
Cited by 10 | PDF Full-text (4663 KB) | HTML Full-text | XML Full-text
Abstract
The detonation gun sprayed Fe-Al type coatings as an alternative for austenitic valve steel, were investigated using two different methods of testing corrosion resistance. High temperature, 10-hour isothermal oxidation experiments at 550, 750, 950 and 1100 °C show differences in the oxidation behavior
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The detonation gun sprayed Fe-Al type coatings as an alternative for austenitic valve steel, were investigated using two different methods of testing corrosion resistance. High temperature, 10-hour isothermal oxidation experiments at 550, 750, 950 and 1100 °C show differences in the oxidation behavior of Fe-Al type coatings under air atmosphere. The oxide layer ensures satisfying oxidation resistance, even at 950 and 1100 °C. Hematite, α-Al2O3 and metastable alumina phases were noticed on the coatings top surface, which preserves its initial thickness providing protection to the underlying substrate. In general, only negligible changes of the phase composition of the coatings were noticed with simultaneous strengthening controlled in the micro-hardness measurements, even after 10-hours of heating at 1100 °C. On the other hand, the electrochemical corrosion tests, which were carried out in 200 ppm Cl (NaCl) and pH ~4 (H2SO4) solution to simulate the acid-rain environment, reveal higher values of the breakdown potential for D-gun sprayed Fe-Al type coatings than the ones for the bulk Fe-Al type alloy and Cr21Mn9Ni4 austenitic valve steel. This enables these materials to be used in structural and multifunctional applications in aggressive environments, including acidic ones. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)
Open AccessArticle Characterization of Low-Symmetry Structures from Phase Equilibrium of Fe-Al System—Microstructures and Mechanical Properties
Materials 2015, 8(3), 914-931; doi:10.3390/ma8030914
Received: 20 December 2014 / Revised: 12 February 2015 / Accepted: 15 February 2015 / Published: 4 March 2015
Cited by 12 | PDF Full-text (3025 KB) | HTML Full-text | XML Full-text
Abstract
Fe-Al intermetallic alloys with aluminum content over 60 at% are in the area of the phase equilibrium diagram that is considerably less investigated in comparison to the high-symmetry Fe3Al and FeAl phases. Ambiguous crystallographic information and incoherent data referring to the
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Fe-Al intermetallic alloys with aluminum content over 60 at% are in the area of the phase equilibrium diagram that is considerably less investigated in comparison to the high-symmetry Fe3Al and FeAl phases. Ambiguous crystallographic information and incoherent data referring to the phase equilibrium diagrams placed in a high-aluminum range have caused confusions and misinformation. Nowadays unequivocal material properties description of FeAl2, Fe2Al5 and FeAl3 intermetallic alloys is still incomplete. In this paper, the influence of aluminum content and processing parameters on phase composition is presented. The occurrence of low-symmetry FeAl2, Fe2Al5 and FeAl3 structures determined by chemical composition and phase transformations was defined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) examinations. These results served to verify diffraction investigations (XRD) and to explain the mechanical properties of cast materials such as: hardness, Young’s modulus and fracture toughness evaluated using the nano-indentation technique. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)
Open AccessArticle The Structure of FeAl Sinters Fabricated Using Cyclic Loading
Materials 2015, 8(2), 575-585; doi:10.3390/ma8020575
Received: 21 January 2015 / Accepted: 30 January 2015 / Published: 9 February 2015
Cited by 3 | PDF Full-text (1757 KB) | HTML Full-text | XML Full-text
Abstract
A two stage process including a sintering under a cyclic loading is proposed as an alternative fabrication method of dense FeAl intermetallics from elemental powder mixtures. The first stage (pre-sintering) is conducted at two temperature values (620 °C and 670 °C, respectively) under
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A two stage process including a sintering under a cyclic loading is proposed as an alternative fabrication method of dense FeAl intermetallics from elemental powder mixtures. The first stage (pre-sintering) is conducted at two temperature values (620 °C and 670 °C, respectively) under a static and a cyclic loading with a frequency of 20, 40 and 60 Hz. The second one includes a pressureless sintering at temperature of 1250 °C, under a protective argon atmosphere. A suitable selection of pre-sintering parameters (temperature, type and frequency of pressing) allows approximately five times grain size reduction of FeAl phase in comparison to particle size of raw Fe and Al powder material (40–60 µm), as well as induces an effective fragmentation of oxide layers. For the sinters obtained using 60 Hz loading frequency an oxide particle size of 4.0 or 4.5 µm (smaller for sintering with liquid phase) is observed. Material obtained after the full heat treatment are characterized by a fine-grained structure of chemically homogeneous FeAl phase with uniformly distributed Al2O3 spherical particles along grain boundaries. Moreover, it was found that temperature and frequency of loading during the presintering process also affect a consolidation level of the Fe-Al powder mixture, which increases with rising both temperature and frequency. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)

Review

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Open AccessReview Applications of Ni3Al Based Intermetallic Alloys—Current Stage and Potential Perceptivities
Materials 2015, 8(5), 2537-2568; doi:10.3390/ma8052537
Received: 21 January 2015 / Revised: 20 April 2015 / Accepted: 23 April 2015 / Published: 13 May 2015
Cited by 22 | PDF Full-text (8003 KB) | HTML Full-text | XML Full-text
Abstract
The paper presents an overview of current and prospective applications of Ni3Al based intermetallic alloys—modern engineering materials with special properties that are potentially useful for both structural and functional purposes. The bulk components manufactured from these materials are intended mainly for
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The paper presents an overview of current and prospective applications of Ni3Al based intermetallic alloys—modern engineering materials with special properties that are potentially useful for both structural and functional purposes. The bulk components manufactured from these materials are intended mainly for forging dies, furnace assembly, turbocharger components, valves, and piston head of internal combustion engines. The Ni3Al based alloys produced by a directional solidification are also considered as a material for the fabrication of jet engine turbine blades. Moreover, development of composite materials with Ni3Al based alloys as a matrix hardened by, e.g., TiC, ZrO2, WC, SiC and graphene, is also reported. Due to special physical and chemical properties; it is expected that these materials in the form of thin foils and strips should make a significant contribution to the production of high tech devices, e.g., Micro Electro-Mechanical Systems (MEMS) or Microtechnology-based Energy and Chemical Systems (MECS); as well as heat exchangers; microreactors; micro-actuators; components of combustion chambers and gasket of rocket and jet engines as well components of high specific strength systems. Additionally, their catalytic properties may find an application in catalytic converters, air purification systems from chemical and biological toxic agents or in a hydrogen “production” by a decomposition of hydrocarbons. Full article
(This article belongs to the Special Issue Intermetallic Alloys: Fabrication, Properties and Applications)
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