A phenomenological study of the influence of the hardening type on the indentation F-h cyclic curve

Abstract

This paper is a phenomenological study representing the influence of the hardening type on the instrumented indentation F-h curve. Spherical instrumented indentation and inverse analysis techniques (IAT) are used and two metallic materials (DP600 and AA2017) are investigated. Pure isotropic (Voce) and combined (Chaboche 1986) hardening laws are adopted for describing the plastic behavior of the studied materials. The influence of the hardening type on the indentation loading curve is studied first. Kinematic hardening results in softening the indentation loading curve. This is due to some regions in the indented zone that undergo different loading paths during loading. Hardening types (kinematic & isotropic) should be considered to accurately characterize the mechanical behaviour of different metallic materials using indentation curves. The influence of the hardening type on the indentation unloading-reloading curve (hysteresis loop) is then studied. Kinematic hardening has an important influence on the hysteresis loop. This influence has been investigated closely and a methodology is proposed for estimating the contribution of each hardening type in the overall hardening behavior. This methodology is based on geometrical parameters directly influenced by the hardening type and presents great potential if considered in future works aiming to identify parameters of relatively complex hardening laws using the instrumented indentation technique (IIT).