Imperial College London
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ProfessorDavidDye

Faculty of Engineering, Department of Materials

Professor of Metallurgy
 
 
 
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Contact

 

+44 (0)20 7594 6811david.dye

 
 
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Location

 

1.09GoldsmithSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Joseph:2020:10.1016/j.ijplas.2020.102743,
author = {Joseph, S and Joseph, K and Lindley, TC and Dye, D},
doi = {10.1016/j.ijplas.2020.102743},
journal = {International Journal of Plasticity},
title = {The role of dwell hold on the dislocation mechanisms of fatigue in a near alpha titanium alloy},
url = {http://dx.doi.org/10.1016/j.ijplas.2020.102743},
volume = {131},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The dislocation structures appearing in highly mis-oriented soft/hard grain pairs in near-alphatitanium alloy Ti6242Si were examined with and without the application of load holds (dwell)during fatigue. Dislocation pile-up in a soft grain resulted in internal stresses in an adjacent hardgrain which could be relaxed by dislocation multiplication at localised Frank–Read sources, aprocess assisted by the provision of a relaxation time during a load hold. The rate of this processis suggested to be controlled by+pyramidal cross-slip andbasal junction formation.A high density ofprism pile-ups was observed with dual slip on two prism planes, togetherwith edge dislocations on the third prism plane in the soft grain of a highly mis-oriented grainpair, increasing the pile-up stress. The stress concentration developed by such pile-ups is foundto be higher in dwell fatigue (single-ended pile-ups) than in LCF (double ended). Analyticalmodelling shows that the maximum normal stress produced on the hard grain in dwell fatigueby this pile-up would be near-basal,≈ 2.5to (0002). This provides support for the dominanthypothesis for the rationalisation of dwell fatigue crack nucleation in Ti alloys, which derivesfrom the Stroh pile-up model, and elaboration of the underlying dislocation phenomena thatresult from load shedding and lead to basal faceting.
AU  - Joseph,S
AU  - Joseph,K
AU  - Lindley,TC
AU  - Dye,D
DO  - 10.1016/j.ijplas.2020.102743
PY  - 2020///
SN  - 0749-6419
TI  - The role of dwell hold on the dislocation mechanisms of fatigue in a near alpha titanium alloy
T2  - International Journal of Plasticity
UR  - http://dx.doi.org/10.1016/j.ijplas.2020.102743
UR  - https://www.sciencedirect.com/science/article/pii/S0749641919307600?via%3Dihub
UR  - http://hdl.handle.net/10044/1/80768
VL  - 131
ER  -
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