J. Phys. IV France 112 (2003) 1147
Shape recovery and stress-induced martensite in TiNi following indentation and wear loadingW. Ni1, Y.-T. Cheng1 and D.S. Grummon2
1 Materials and Processes Laboratory, General Motors Research and Development Center, Warren, MI 48090, USA
2 Department of Chemical Engineering and Materials Science, 3525 Engineering Building, Michigan State University, East Lansing, MI 48824, USA
We present initial findings that are suggestive of the potential for shape-memory and superelastic NiTi alloys to function as useful tribological materials. For example, surface-deformation made with a spherical indenter is found to be almost completely recoverable by the shape-memory effect. A similar form of strain recovely is shown to be possible in thin films and in wear-track profiles. When a martensitic material is subjected to pin-on-disk loading, a substantial fraction of the wear track cross-section can be recovered by heating. It is also shown that the martensite phase can be stress-induced in response to complex loading associated either indentation or pin-on-disk wear tests, indicating that transformational superelasticity may be able to ameliorate wear degradation in the same way that it can limit low-cycle fatigue damage accumulation. Since NiTi can readily be deployed as a sputtered thin film coating, it may be possible to confer these beneficial effects to base metal substrates such as aluminum.
© EDP Sciences 2003