High temperature deformation of age hardening coatings
Researcher: Constantin Ciurea
Funding: Centre for Advanced Structural Ceramics
Traditional materials become softer as they are heated. The goal of this project is study a recently developed class of ceramics which increase their strength at high temperature (ternary nitrides e.g. TiAlN). These have found widespread use as high temperature cutting tools but a fundamental understanding of the hardening mechanisms is lacking. This limits further optimization of the material system.
Initial work has centred on accurately measuring the hardness of TiN and TiAlN over a range of temperatures and strain rates to extract the fundamental parameters of deformation such as activation volume and peierls stress. In parallel the films have been carefully characterised by XRD and TEM.
Future work will centre on understanding how different processing routes, such as magnetron sputtering or cathodic arc, affect the high temperature properties. Also annealing experiments within the TEM will be carried out to observe the microstructural changes and hopefully the underlying mechanisms of structural refinement, for example nucleation and growth or spinodal decomposition.