Special Issue "High Temperature Alloys and Intermetallic Materials"

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

Deadline for manuscript submissions: 25 December 2019.

Special Issue Editor

Guest Editor
Prof. SARA BIAMINO Website E-Mail
Politecnico di Torino, Department of Applied Science and Technology, Torino, Italy
Interests: additive manufacturing; high temperature materials; Ni superalloys; Titanium Aluminides; titanium alloys; relationships microstructure-properties

Special Issue Information

Dear Colleagues,

Nowadays the request for materials able to efficiently operate at ever-higher service temperatures is continuously pushing research activities in many industrial sectors. In particular, in the field of power generation, aerospace and automotive, it is of fundamental importance in order to increase the efficiency of the engines, thus reducing fuel consumption and pollutant emissions moving towards greener engines. Ever-higher temperatures mean moving to ever-more severe conditions for materials that require improved mechanical properties, but also oxidation and corrosion resistance.

The Special Issue, “High Temperature Alloy and Intermetallic Materials”, will address advances in materials science, processing, characterization, new components development as well as the testing of new systems of materials for high temperatures, thus providing readers with up-to date information on the recent progress from different perspectives.

It is my pleasure to invite you to submit a manuscript to this Special Issue. Original papers are solicited on metallic alloys and intermetallic materials in the following areas:

  • New chemical compositions for increased properties
  • New processing routes
  • New characterizations
  • New coatings for thermal protection
  • New findings in their oxidation and corrosion

Full papers, communications and reviews are all welcome.

Prof. SARA BIAMINO
Guest Editor

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 semimonthly 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 1800 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

  • Metallic alloys
  • intermetallics
  • new alloys
  • coatings
  • processing routes
  • microstructure characterization
  • mechanical properties
  • oxidation
  • corrosion

Published Papers (2 papers)

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Research

Open AccessArticle
Effects of Cr, W, and Mo on the High Temperature Oxidation of Ni-Based Superalloys
Materials 2019, 12(18), 2934; https://doi.org/10.3390/ma12182934 - 11 Sep 2019
Abstract
The oxidation behavior of Ni–9.5Co–(8~12)Cr–(2.5~5.5)Mo–(4~8)W–3Al–5Ti–3Ta–0.1C–0.01B alloys was investigated at 850 °C and 1000 °C The mass change, the phase of oxides, and the cross-sectional structure of specimens were analyzed after cyclic oxidation tests. The oxide scale was composed mainly of Cr2O [...] Read more.
The oxidation behavior of Ni–9.5Co–(8~12)Cr–(2.5~5.5)Mo–(4~8)W–3Al–5Ti–3Ta–0.1C–0.01B alloys was investigated at 850 °C and 1000 °C The mass change, the phase of oxides, and the cross-sectional structure of specimens were analyzed after cyclic oxidation tests. The oxide scale was composed mainly of Cr2O3 and NiCr2O4, but NiO, TiO2, and CrTaO4 were also found. Al2O3 was formed beneath the Cr oxide layer. The Cr oxide layer and internal Al oxide acted as barriers to oxidation at 850 °C, while Al oxide was predominantly protective at 1000 °C. Cr increased the mass gain after oxidation test at both temperatures. Mo increased the oxidation rate at 850 °C but decreased the oxidation rate at 1000 °C. W slightly increased the mass gain at 850 °C but did not produce a significant effect at 1000 °C. The effects of Cr, Mo, W, and the temperature were discussed as well as the volatilization of oxides, the valence number of elements, and diffusion retardation. Full article
(This article belongs to the Special Issue High Temperature Alloys and Intermetallic Materials)
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Open AccessFeature PaperArticle
Microstructural Evolution of Post-Processed Hastelloy X Alloy Fabricated by Laser Powder Bed Fusion
Materials 2019, 12(3), 486; https://doi.org/10.3390/ma12030486 - 05 Feb 2019
Cited by 1
Abstract
Hastelloy X (HX) is a Ni-based superalloy which is employed to produce gas turbine and gas-cooled reactor sectors due to its outstanding oxidation resistance and high tensile strength at high temperatures. This alloy can be processed by laser powder bed fusion (LPBF) fabricating [...] Read more.
Hastelloy X (HX) is a Ni-based superalloy which is employed to produce gas turbine and gas-cooled reactor sectors due to its outstanding oxidation resistance and high tensile strength at high temperatures. This alloy can be processed by laser powder bed fusion (LPBF) fabricating complex geometries in a single step. However, post-processing thermal treatments must be applied to generate a suitable microstructure for high-temperature applications. The investigation reports the microstructure evolution of LPBF HX samples under specific post-processing treatments. A hot isostatic pressing (HIP) treatment can close the internal cracks and reduce the residual porosity (less than 0.1%). Moreover, the HIP-triggered recrystallization generated equiaxed grains, while the slow cooling rate generated a film of intergranular carbides (Mo-rich M6C and Cr-rich M23C6) and intragranular carbides (Mo-rich M6C carbides). Therefore, a solution annealing was performed to dissolve the film of carbides which may reduce the ductility. The post solution annealed material consisted of equiaxed grains with ASTM grain size number mainly 4.5-5.5 and inter/intragranular Mo-rich M6C carbides. The microstructure is highly comparable with solution annealed wrought HX alloy. Finally, after simulating short thermal exposure at 745 °C for 6 h, a significant formation of Cr-rich M23C6 carbides was observed strengthening the LPBF HX alloy. Full article
(This article belongs to the Special Issue High Temperature Alloys and Intermetallic Materials)
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