Influence of Shot Peening on the Isothermal Fatigue Behavior of the Gamma Titanium Aluminide Ti-48Al-2Cr-2Nb at 750 °C
| Autor: | Elias Gall, Jens Gibmeier, Radosław Swadźba, Christoph Breuner, Martin Heilmaier, Stefan Guth |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
intermetallic residual stress 02 engineering and technology Shot peening 01 natural sciences Indentation hardness high temperature Stress (mechanics) chemistry.chemical_compound Residual stress 0103 physical sciences Ultimate tensile strength General Materials Science Composite material Engineering & allied operations 010302 applied physics Titanium aluminide Mining engineering. Metallurgy TN1-997 Metals and Alloys 021001 nanoscience & nanotechnology Hardness chemistry gamma titanium aluminide shot peening fatigue ddc:620 0210 nano-technology Electron backscatter diffraction |
| Zdroj: | Metals, 11 (7), Art.-Nr.: 1083 Metals Volume 11 Issue 7 Metals, Vol 11, Iss 1083, p 1083 (2021) |
| ISSN: | 2075-4701 |
| Popis: | One possibility to improve the fatigue life and strength of metallic materials is shot peening. However, at elevated temperatures, the induced residual stresses may relax. To investigate the influence of shot peening on high-temperature fatigue behavior, isothermal fatigue tests were conducted on shot-peened and untreated samples of gamma TiAl 48-2-2 at 750 °C in air. The shot-peened material was characterized using EBSD, microhardness, and residual stress analyses. Shot peening leads to a significant increase in surface hardness and high compressive residual stresses near the surface. Both effects may have a positive influence on lifetime. However, it also leads to surface notches and tensile residual stresses in the bulk material with a negative impact on cyclic lifetime. During fully reversed uniaxial tension-compression fatigue tests (R = −1) at a stress amplitude of 260 MPa, the positive effects dominate, and the fatigue lifetime increases. At a lower stress amplitude of 230 MPa, the negative effect of internal tensile residual stresses dominates, and the lifetime decreases. Shot peening leads to a transition from surface to volume crack initiation if the surface is not damaged by the shots. |
| Databáze: | OpenAIRE |
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