Microstructural insights into the influence of stress amplitudes on the crack nucleation mechanism of Ti–2Al-2.5Zr alloy using quasi in-situ tests
The fatigue cracking mechanism of Ti–2Al-2.5Zr alloy was investigated under different stress amplitudes. The evolution of fatigue damage was analyzed using quasi in-situ tests. The dependence of transgranular and intergranular crack nucleation on microstructure features was discussed in detail. The...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-03-01
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| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425000274 |
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| Summary: | The fatigue cracking mechanism of Ti–2Al-2.5Zr alloy was investigated under different stress amplitudes. The evolution of fatigue damage was analyzed using quasi in-situ tests. The dependence of transgranular and intergranular crack nucleation on microstructure features was discussed in detail. The mechanisms of slip-induced and twinning-detwinning (T-D) induced crack nucleation were elucidated, respectively. It was found that, at the stress amplitude of 442 MPa, the slip damage, in the form of intrusions/extrusions, dominated crack nucleation. Transgranular cracks primarily nucleate along the prismatic planes of the variants with highest Schmid Factor of prismatic slip (SFpris.); intergranular cracks are mainly induced at grain boundaries (GBs) by slip impacting/shearing GB behaviors and at GB triple junctions due to strain incompatibility. As the stress amplitude increased to 475 MPa, the dominant crack mode transitioned from slip-dominant cracks to T-D induced cracks and intergranular cracks due to the competition between the T-D and slip behavior. Twin boundaries (TBs), GBs, slip planes adjacent to the activated T-D regions, and the twin pairs/chains in adjacent grains were identified as preferred sites for crack nucleation. |
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| ISSN: | 2238-7854 |