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| Failure Mechanisms | |||||||||||||||||
| ·
Creep
controlled by either grain boundary or bulk diffusion becomes important
at temperatures above about 0.5 Tm.
· In materials where the applied stress is below that required to activate Frank-Reed sources and cause dislocation controlled creep, these transport processes are the main creep mechanism. · The transition between control by bulk diffusion rather than grain boundary diffusion will depend upon temperature because of the lower activation energy associated with grain boundary transport, |
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| From:
Newey and Weaver,
"Materials Principles and Practice," Butterworths (1990) |
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| and on microstructure because of the effective area of the boundaries versus the bulk. | |||||||||||||||||