SGER: Proof of Concept Experiments for Novel Tribological Systems: Superelastic Response in Sputtered Tinix Film Coatings

Michigan State University, East Lansing MI

Investigators

Abstract

Proof of Concept Experiments for Novel Tribological Systems: Superelastic Response in sputtered TiNiX Film Coatings Abstract -- Shape-memory, and especially superelastic alloys, are of interest as tribological materials because they express large and reversible strain excursions without accumulating lattice damage from dislocation-mediated slip. Recent experiments at General Motors Research Laboratories and at Michigan State University have established the robust operation of both shape-memory and superelastic effects during localized microscale deformation. In this project we will explore the potential for functional vapor-deposited thin films of nickel-titanium shape-memory and superelastic alloys to enhance compliance and limit damage accumulation in wear processes. If successful, the project could have very substantial impact in many tribological applications for sleeve bearings, etc. By deploying a sputtered thin film coating of superelastic NiTi, either as a functionally graded surface film, or as an interlayer between a metallic substrate and a conventional hard-coating, we will attempt to confer the beneficial tribological effects of superelasticity to base-metal substrates. The principal objective of the project will be to demonstrate that sputtered TiNi films, integrated with tailored hard coatings, will show significantly better wear resistance than conventional coatings alone. The technique will also be evaluated for its ability to improve hard-coating adhesion by ameliorating severe thermal expansion and elastic constant mismatches between the coating and base materials, particularly for aluminum alloy substrates.