Deformation mechanisms in a WC–Co based cemented carbide during creep

Artikel i vetenskaplig tidskrift, 2015

The microstructure of a WC–Co based cemented carbide has been investigated before and after plastic deformation at high temperatures. The material was fabricated with a Co binder phase content of 16 vol.% and smaller additions of Cr. Hot compressive creep tests were performed under an applied load of 900 MPa at 1000 and 1100 °C. The test bars were deformed to 10 or 20% strain at 1000 °C, and to 7% strain at 1100 °C. Quantitative microscopy using SEM suggests that WC grain growth took place during the creep tests, and that the growth took place preferentially in the plane perpendicular to the load axis. TEM showed that there was an increased dislocation density in the WC grains after creep deformation. Deformation was also associated with a redistribution of the WC grains resulting in the formation of intergranular binder phase lamellae and cavities. EBSD showed that there was an increased spread in the crystallographic orientation of the binder phase after deformation.