Vanadium Carbide in Tempered Martensite

S. Yamasaki and H.K.D.H. Bhadeshia

• The micrographs are published in Materials Science and Technology, Vol. 19 (2003) 1335-1343.
• Tempered Martensite
• Martensitic Transformations.
• Imaging atom-probe study.

Crystal Structure of Vanadium Carbide

Vanadium carbide (VC) has a cubic-F lattice with a motif of a vanadium atom at 0,0,0 and a carbon atom at 0,0,0.5. However, although illustrated here as a stoichiometric carbide, the carbon concentration tends to be less than 50%. There are also ordering reactions that occur in the carbide which are not illustrated here. The lattice parameter is assumed to be 0.4159 nm. The blue atoms represent vanadium and carbon is designated black.

Vanadium carbide: projection of crystal structure along 101 direction	Vanadium carbide: projection of crystal structure along a 111 direction
Vanadium carbide: projection of crystal structure along a cube edge	Movie 1 of crystal structure being rotated Movie 2 of crystal structure being rotated Movie 3 of crystal structure being rotated Crystalmaker file

Transmission Electron Microscopy

The following micrographs are taken from thin-foil samples studied using a transmission electron microscope.

Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.
Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.
Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.
Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.
Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.
Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.	Tempered martensite in Fe-V-C steel.

Titanium-vanadium carbide in steel

A. R. Waugh

An imaging atom-probe study of a mixed carbide particle in a steel containing titanium and vanadium. Bob wanted to confirm that there is a disturbance in the trajectories of the carbon at the edges of the particle, since the carbon distribution goes beyond the boundaries of the carbide particle. The possibility of such an aberration had been suggested to him by P. Turner.

Photographs courtesy of Dr Sally Waugh.

Titanium/vanadium carbide in steel, imaged while the specimen is at 60 K.

Neon field-ion image. .	An image with just the Fe2+ ions, showing the absence of iron in the carbide particle.
An image using the carbon C2+ ions.	Combined image of the C2+ ions superimposed on the field-ion image.

Schematic of imaging atom probe apparatus.