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:
Samples of Ti-15Cr and Ti-15V-3Sn-3Al-3Cr (wt%) containing controlled additions ofcarbon up to 0.2wt% and different oxygen contents have been quenched and aged at temperaturesbetween 400 and 600°C. Optical, scanning and analytical transmission electron microscopy havebeen used to characterise the microstructures of the quenched and aged samples. Hardness testinghas been used to follow the kinetics and extent of age hardening, which are accelerated in Ccontainingsamples. The addition of carbon results in the formation of Ti(CxOy) precipitates whichpin grain boundaries in forged samples so that the grain size in the quenched C-containing samplesis about a factor of ten less than that in the C-free samples. In the C-free samples coarse grainboundary alpha tends to form, but in the C-containing samples alpha precipitation is more uniformthroughout the beta grains. The extent of omega precipitation is very different in the two alloys; theTi-15Cr alloy forms athermal omega in the as-quenched samples and large omega precipitates areformed on ageing at 400°C. No evidence for omega has been obtained in the Ti-15-3. Thehardening responses and microstructural observations are interpreted in terms of the different grainboundary oxygen contents in the C-containing and C-free samples and the different roles of omegaand of carbon in the two alloys
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/15/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.539-543.3595.pdf
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