High Temperature Deformation Mechanisms in WC-Ni 3Al Cermets

The microstructure and mechanical properties of WC-Ni₃ composites were examined after compression in the temperature range of 650-900 ℃. At these temperatures, antiphase boundaries were generated in the Ni₃Al binder phase. Due to this mechanism, the WC-10%Ni₃Al sample exhibits high compressive strengths of ~1300-1650 MPa at elevated temperatures. TEM analysis indicates that plastic accommodation during the deformation process is primarily due to deformation of both the WC and the Ni₃Al binder. Yield loci slip mode analysis was used to confirm that dislocations, stacking faults, and even twins can exist on the prismatic plane {01‾10} in WC at high temperatures. This type of combined strengthening from both the matrix and binder provides a new strategy to improve the high-temperature mechanical properties of cemented carbides. Moreover, Ni₃Al becomes a promising alternative intermetallic to Co as a binder.