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:
The growth mechanism of bainitic α plates in Ti-4.5Fe-6.8Mo-1.5Al, a metastable β Tialloy, has been investigated by optical microscopy, electron probe microanalysis (EPMA) anddilatometry. The observations are compared with the transformation characteristics of primary αplates, which form at relatively high temperatures. The primary α plates form predominantly on βgrain boundaries, whereas the bainitic α plates nucleate both at grain boundaries andintragranularly. It is shown that the morphological transition with decreasing temperature isassociated with a change in transformation mechanism. The EPMA results show that the primary αplates are formed by a partitioning transformation. In contrast, the growth of the bainitic α plates ispartitionless, followed by a post-transformation redistribution of Fe. This mechanism is similar tobainite in steel. The Fe diffusion from the supersaturated bainitic α plates to the β matrix causes theobserved dilatation signal. The results of dilatometry in conjunction with optical microscopyindicate that a low misfit between the lattice structures exists, which is favourable for a partitionlesstransformation to occur at a low undercooling below T0
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/15/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.539-543.3684.pdf
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