Abstract
The tensile creep properties of a beta-rich (Ni,Pt)Al diffusion coating have been determined at various strains over the temperature range 800-1000 degrees C by deconvoluting the creep response of layered composite specimens under constant stress conditions. It is found that the creep strength of the diffusion coating tends to be higher than that of a similar coating tested previously by Pan et al. [Pan D, Chen MW, Wright PK. Hemker KJ. Acta Mater 2003;51:2205]. Associated with the higher strength is a relatively high creep activation energy (similar to 600 kJ/mol) and a high stress dependence of creep rate which increases with creep strain front similar to 6.8 at 1% strain to similar to 9.4 at 9% strain. These high values and the associated high creep strength are attributed to the formation. at the creep temperatures. of a fine dispersion of second-phase particles, presumed to be gamma' and possibly alpha-Cr within the beta-(Ni,Pt)Al matrix. It is suggested that the extent of this transformation and, hence. the strengthening effect are related to the original aluminium and platinum content of the coating. (c) 2006 Acta Materiatia Inc. Published by Elsevier Ltd. All rights reserved.
Original language | English |
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Pages (from-to) | 3241-3252 |
Number of pages | 12 |
Journal | Acta Materialia |
Volume | 54 |
Issue number | 12 |
DOIs | |
Publication status | Published - 1 Jul 2006 |
Keywords
- Pt-aluminide
- creep
- bond coat
- TBC