Study of stress localisation in polycrystalline grains using self-consistent modelling and neutron diffraction

Abstract

The time-of-flight neutron diffraction technique and the elastoplastic self-consistent model were used to study the behaviour of single and multi-phase materials. Critical resolved shear stresses and hardening parameters in austenitic and austenitic–ferritic steels were found by analysing the evolution of the lattice strains measured during tensile tests. Special attention was paid to the changes of the grain stresses occurring due to transition from elastic to plastic deformation. Using a new method of data analysis, the variation of the stress localisation tensor as a function of macrostress was measured. The experimental results were successfully compared with model predictions for both phases of the duplex steel and also for the austenitic sample.

Keywords:

• neutron diffraction
• multiscale modelling
• stress–strain measurement
• polycrystalline metal
• plastic deformation

Acknowledgements

This work was partly supported by the Polish National Centre for Science (NCN) under decision numbers DEC-2011/01/D/ST8/07399 and DEC-2011/01/B/ST8/07394 and by the Polish Ministry of Science and Higher Education (MNiSW). Experiments at the ISIS Pulsed Neutron and Muon Source were supported by a beamtime allocation (RB820145) from the Science and Technology Facilities Council. A PhD grant for Ms. Le Joncour was given by the French Ministry of Research and Higher Education.