| dc.description.abstract | Titanium carbonitride (Ti(C,N)) cermets have become more popular in recent research
due to their mix of high hardness, high hot hardness, good ductility, chemical stability,
and low densities. These mechanical properties make Ti(C,N)-cermets especially
desirable as a replacement for current ‘hardmetals’, such as tungsten carbide cobalt (WCCo),
as it is known that WC-Co exhibits poor mechanical behaviour at elevated
temperatures. Additional interest and research has been conducted in reference to binders
which enhance the cermet’s capability to retain strength at high temperatures while
remaining ductile. One such binder, Ni3Al actually increases in yield strength up to a
temperature of ~900°C. In this thesis, the production method utilizing melt infiltration for
TiC, Ti(C0.7,N0.3), Ti(C0.5,N0.5), and Ti(C0.3,N0.7)-based cermets with Ni3Al binder
contents of 20, 30 and 40 vol. % have successfully been developed and utilized. This
process produced high density samples at each nitrogen content for all binder contents,
excluding Ti(C0.3,N0.7). Ti(C0.3,N0.7)-Ni3Al samples at 20 and 30 vol. % suffered from
poor infiltration and could not be tested. The reciprocating wear mechanisms were
examined, using a ball-on-flat test, utilizing WC-Co spheres with a diameter of 6.35 mm
as a counter-face, and test parameters of 20 Hz, 2 hrs., and applied loads of 20, 40, 60 and
80 N. The wear tracks were examined using optical profilometry, SEM, and EDS to
determine the volumetric wear rate, and the dominant wear mechanisms. The wear
volume, and wear mechanisms were compared with the effect of binder content, nitrogen
content, and applied load. | en_US |
