Phase Diagram-based Microstructure Design Principle of High-temperature Structural Intermetallic/Metallic Materials and the Role of Grain Boundaries in Strengthening

Materia Japan ◽  
2021 ◽  
Vol 60 (5) ◽  
pp. 281-288
Author(s):  
Masao Takeyama
Keyword(s):  
Phase Diagram ◽  
High Temperature ◽  
Grain Boundaries ◽  
Design Principle ◽  
Metallic Materials ◽  
Microstructure Design ◽  
Structural Intermetallic

The role of microscopy in the alloy design of Ni- and Fe-based aluminides

1992 ◽  
Vol 50 (1) ◽  
pp. 168-169
Author(s):  
J.A. Horton
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Oxidation Resistance ◽  
Industrial Applications ◽  
Al Alloys ◽  
Ordered Alloys ◽  
Successful Control ◽  
Oxidation Resistant

During the last 10 years, there has been a resurgence of interest in ordered alloys for structural uses due to the discovery of the dramatic ductilizing effect of boron on grain boundaries in Ni3Al. With this discovery, it was hoped that the property of an increase in strength as the temperature is increased could be utilized as well as the excellent oxidation resistance. Now, alloys based on Ni3Al are in use in specialized industrial applications, such as high temperature forging dies and being tested for use as turbocharger rotors. Due to the successful control of the grain boundary strength in Ni3Al, other systems were reexamined. For example, Fe3Al was also thought to have inherently brittle grain boundaries, however it was found that with purer alloys the material failed by cleavage. Subsequently, development of practical, inexpensive, oxidation resistant alloys has proceeded. Fe3Al alloys are currently being tested for automobile exhaust applications.

Computer Modelling of Grain Boundaries for Optimizing the Properties of Polycrystalline Metallic Materials

2009 ◽  
Vol 618-619 ◽  
pp. 207-214 ◽  
Author(s):  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Corrosion Resistance ◽  
Grain Boundaries ◽  
Recent Progress ◽  
Computer Modelling ◽  
Metallic Materials ◽  
Grain Sizes

Grain boundaries significantly influence the properties of polycrystalline metallic materials, particularly with grain sizes in the nano-metre range. The effect of grain boundaries on plasticity, fracture and corrosion resistance is well documented experimentally. The aim of this paper is to show that recent progress in modelling of the role of grain boundaries in metallic materials offers new possibilities for optimizing their properties.

The Role of Zr in the High-Temperature Oxidation of Fe3Al

2008 ◽  
Vol 595-598 ◽  
pp. 1103-1110 ◽  
Author(s):  
Kazimierz Przybylski ◽  
Sébastien Chevalier ◽  
P. Juzoń ◽  
Alain Galerie ◽  
Günter Borchardt ◽  
...  
Keyword(s):  
High Temperature ◽  
Grain Boundaries ◽  
High Temperature Oxidation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Oxidation Mechanism ◽  
Analytical Techniques ◽  
Alumina Layer ◽  
Temperature Oxidation

The paper describes an examination of the effect of the addition of zirconium as a third element on the heat-resisting properties and explains the high temperature oxidation mechanism of Fe3Al intermetallic compounds. The Fe3Al and Fe3Al-0,05Zr specimens have been isothermally oxidized in the temperature range of 1173-1473 K in synthetic air for 100 hrs. The formed oxide layer, about 1,5-2 μm thick, was Al2O3. An examination of the cross-sectioned scales by SEM-EDS showed that the alumina layer consisted of a small inner columnar layer and an outer equiaxed grain layer. Additionally, very fine (50-150 nm) oxide grains rich in Zr, further identified as ZrO2, were found across the alumina scales. To understand the role of Zr on the growth mechanism of α–Al2O3 oxide scale on Fe3Al materials, two-stage oxidation experiments were performed (16O2/18O2), followed by SIMS and TEM-SAD observations. Particular attention was paid to the use of TEM in order to precisely characterize the products on samples prepared using the FIB (Focused Ion Beam) method. A combination of analytical techniques revealed that ZrO2 particles, most of which were formed along alumina grain boundaries, enhanced oxygen diffusion along grain boundaries due to oxygen-deficient composition of zirconium oxide (ZrO2-y).

Sign in / Sign up

Export Citation Format

Share Document