Effective structural unit size in titanium alloys

Abstract

This paper introduces the concept of effective structural size in titanium alloys and its importance with respect to material production routes and component lifing/design. Traditionally, process route optimization has relied on optical microscopy, which may be misleading when predicting mechanical properties. Similarly, continuum mechanics and current lifing methods are based on empirical data analysis. The advent of advanced material characterization techniques, e.g. EBSD combined with crystal plasticity modelling, has the potential to provide the next generation of mechanistically sound methods that more accurately predict material behaviour in complex loading regimes. These benefits are reviewed in the context of industrial application. Crystal plasticity modelling techniques are presented and a particular structural unit - termed a rogue grain - in a model single-phase titanium alloy is considered. Cold dwell under both strain and stress control is then assessed in the structural unit.