Pseudoelasticity and Shape Memory Effects on Deformation Recovery of Indented Titanium-Nickel Alloy Films

Abstract

The deformation behavior of shape-memory titanium-nickel (TiNi) alloy films indented by diamond tips of various nominal radius of curvature under different contact loads was investigated by nanoindentation. Pseudoelasticity and shape-memory effect (SME) strongly affected the deformation recovery of the indented films. The effects of tip radius and maximum indentation load on the deformation recovery of austenitic and martensitic TiNi films are interpreted in terms of associated deformation mechanisms controlled by pseudoelasticity, SME, and dislocations. The results reveal the important roles of pseudoelasticity and SME on the capacity of TiNi films to either fully annihilate or partially recover from deformation induced by nanoindentation, illustrating a high potential for applications requiring large reversible deformations.