GNDs near indents in Ti

Indentation tests of various kinds have been used to assess the plastic flow stress of metals for over a century. Despite this substantial history there is still a great deal of uncertainty concerning the stress and strain fields near an indent, particularly for small indents for which the flow field is contained within a single grain. The anisotropy of the plastic, and indeed elastic, response of HCP Ti make the grain to grain variation in behaviour quite strong. We have used high resolution EBSD, AFM and crystal plasticity based finite element simulations to study the deformation near indents made in basal and prism planes. The EBSD measurements show compressive radial, and tensile hoop stresses near the indents as expected. The lattice rotations mapped by EBSD have allowed the distribution of GNDs near the indent to be constructed. This combined with the modeling gives a very detailed account of the deformation occurring near these indents.

hardness and modulus
rotation fields
GND distributions

Contact: Ben Britton and Angus Wilkinson

The effect of crystal orientation on the indentation response of commercially pure titanium: experiments and simulations
TB Britton, H Liang, FPE Dunne and AJ Wilkinson
Proceedings of the Royal Society A, (2009), available on-line
doi: 10.1098/rspa.2009.0455