Hold-time fatigue crack growth of Allvac 718Plus
Paper i proceeding, 2010

The hold-time fatigue behaviour of Allvac 718Plus was investigated both in the as-heat treated condition and after long-time exposure at temperature close to the maximum operating limit. At temperatures above 450°C the introduction of 90 s hold-time at maximum load significantly increased the fatigue crack growth rate. Both conditions showed purely cycle dependent behavior at 450°C and close to purely time dependent behavior at 700°C. At 600°C intermediate behavior was observed. The long-time exposure had little effect on the cyclic (0.5 Hz) crack growth rates, but the resistance to crack growth with 90 s hold-time decreased. No microstructural effects of long-time exposure (700°C/140 h + 675°C/460 h) could be observed by SEM, but there were indications that the hardness of the material increases somewhat after exposure.


Tensile dwell

Electron microscopy

Fatigue crack growth


M. Hörnqvist

Leif Viskari

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

Krystyna Marta Stiller

Chalmers, Teknisk fysik, Mikroskopi och mikroanalys

G. Sjob̈erg

7th International Symposium on Superalloy 718 and Derivatives 2010. Pittsburgh, 10-13 October 2010

Vol. 2 705-717
978-161782770-9 (ISBN)





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