Effect of microstructural instability on the creep resistance of an advanced intermetallic γ-TiAl based alloy
| Autor: | Michael Kastenhuber, Svea Mayer, Helmut Clemens, Boryana Rashkova |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Precipitation (chemistry) Mechanical Engineering Metallurgy Alloy Metals and Alloys Intermetallic 02 engineering and technology General Chemistry engineering.material 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Creep Mechanics of Materials Phase (matter) 0103 physical sciences Volume fraction Materials Chemistry engineering Lamellar structure 0210 nano-technology |
| Zdroj: | Intermetallics. 80:1-9 |
| ISSN: | 0966-9795 |
| Popis: | Intermetallic titanium aluminides based on the γ-TiAl phase, such as the β-solidifying TNM alloy, have found application in aerospace and automotive industries. In order to adjust balanced mechanical properties in the TNM alloy a two-step heat treatment is subjected to a hot-die forged material to provide a fine nearly fully lamellar microstructure. However, during the second heat treatment step, beyond a critical temperature, discontinuous precipitation can occur which represents a coarsening process of the fine lamellar α 2 /γ-colonies. This microstructural instability is a limiting factor for the TNM alloy, also regarding the maximum operation temperature. In order to investigate the influence of microstructural instability on creep behavior, microstructures with various progress of discontinuous precipitation and average lamellar spacing were adjusted, creep tested and changes in microstructure examined. The creep tests were conducted at 800 °C and 150 MPa. It is demonstrated that the creep resistance is decreased when discontinuous precipitation exceeds a certain volume fraction, thus, revoking the advantages of a narrow lamellar spacing. |
| Databáze: | OpenAIRE |
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