Effect of TaC on plastic deformation of WC-Co and Ti(C,N)-WC-Co
Journal article, 2006

The plastic deformation resistance of metal cutting inserts made from a WC–Co cemented carbide, a Ti(C, N)–WC–Co cermet and corresponding materials with additions of TaC has been studied. The cermets were produced with both high and low carbon activity, resulting in a total of six materials. Ab initio calculations of some WC/WC grain boundary geometries suggest that both Co and Ta segregate substitutionally to the boundary and improve the grain boundary strength when substituting carbon. However, only Co segregation was found experimentally, probably due to (Ta, W)C formation. Plastic deformation tests were performed with a turning operation under controlled conditions. For the WC–Co, the addition of Ta had a positive effect for lower cutting speeds but at higher speeds the effect was negative. Three-point bending tests indicated a beneficial effect of Ta in WC–Co, which was also confirmed by internal friction (IF) measurements. However, after thermal cycling, the effect of Ta could be smaller, or even negative. The Ta cermet produced with low carbon activity exhibited a better plastic deformation resistance during cutting but no apparent effects of Ta could be seen either in IF measurements or in three-point bending tests of the cermets. However, a correlation was found between plastic deformation during turning and IF spectra. In the cermet materials, binder phase lamella formation promotes grain boundary sliding at high temperatures.

Characterisation

Plastic deformation

Cemented carbides

DFT

Internal friction

Author

Gustaf Östberg

Chalmers, Applied Physics, Microscopy and Microanalysis

Katharina Buss

Ecole Polytechnique Federale De Lausanne

Mikael Christensen

Chalmers, Applied Physics, Materials and Surface Theory

Susanne Norgren

R and D Materials and Processes

Hans-Olof Andrén

Chalmers, Applied Physics, Microscopy and Microanalysis

Daniele Mari

Ecole Polytechnique Federale De Lausanne

Göran Wahnström

Chalmers, Applied Physics, Materials and Surface Theory

Ingrid Reineck

R and D Materials and Processes

International Journal of Refractory Metals and Hard Materials

0263-4368 (ISSN)

Vol. 24 1-2 145-154

Subject Categories

Condensed Matter Physics

DOI

10.1016/j.ijrmhm.2005.04.010

More information

Latest update

5/3/2018 1