ISSN:
1662-9752
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:
Smooth specimens of single crystal (SC) superalloy SRR99 with [001] orientation weresubjected to high-cycle fatigue (HCF) loading at temperatures of 700°C, 760°C, 850°C and 900°C inair atmosphere. The results demonstrated that conditional fatigue strength reached the maximum at760°C and decreases with increasing temperature. Analysis on fracture surface showed a trend forcleavage rupture at 850°C and 900°C and ductile rupture at 700°C and 760°C. Fatigue cracksinitiated at the surface or subsurface were primarily responsible for the ultimate failure. The influenceof testing temperature on fatigue lifetime was studied by examining evolution of the microstructurethrough SEM observation. With the process of cyclic loading at elevated temperatures, the primarycuboidal γ′ precipitates tended to agglomerate and spheroidized, meanwhile a larger number ofsecondary γ′ particles were formed in the γ matrix in specimens fatigue tested at 700°C, which wouldhave a significant effect on the high temperature properties
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/16/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.546-549.1219.pdf
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