ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The thermo-mechanical fatigue (TMF) behaviour of the Nimonic 90 Nickel basesuperalloy has been investigated within two laboratories. In-phase-tests (IP) where the maximummechanical strain occurs at the maximum temperature (850°C), and 180°-out-of-phase-tests (180°OP) where the maximum mechanical strain coincides with the minimum temperature (400°C) havebeen applied. All tests were carried out at varying mechanical strain ranges with a constant strainratio of Rε = - 1. A temperature rate of 5 K/s was used throughout the whole cycle without anyadditional cooling system during decreasing temperature. The fatigue life of 180° OP tests is longercompared to identical IP tests. The stress / mechanical strain hysteresis loops are completelydifferent and some characteristic values are compared to each other. The fracture surfaces observedshow that fatigue crack (or cracks) starts on the external surface and propagates inwards. Thefractures of 180° OP tests are transgranular showing the presence of fatigue striations, while thefractures of IP tests are mixed transgranular and intergranular with no fatigue striations
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/54/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.345-346.347.pdf
Permalink