EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The correlation of digital images obtained during deformation allows quantifying the different components of the local displacement and thus, the 2D local strain tensor. Typically, conventional optic systems for image acquisition lead to maximum strain resolutions ranging few micrometers. During the last five years, the micromechanics research community has been performing huge efforts in order to increase such resolution towards the submicron range, which allows intergranular and intragranular strain characterization in the so-called high-resolution digital image correlation (HRDIC). Coupling the HRDIC values with the crystallographic information obtained by EBSD (Electron Backscattered Diffraction) and slip trace analysis, make it possible to assess and quantify the deformation attributed to different microstructural features such as the activation of specific slip systems, twining, second phases, grain boundaries as well as their size effects on strain distribution. Generally, in terms of strain localization, the deformation distributes in a more homogeneous manner when increasing the testing temperature or decreasing the grain size. However, which of them influence more is not clarified yet. Here, we study the effect of the temperature in the strain localization of a fine grained (1-2 μm) commercially pure titanium processed by friction stir processing (FSP) and we compare the results with those obtained in the same material with a coarser grain size (20 μm). The HRDIC strain maps at two macroscopic deformation steps and two testing temperatures (room temperature and 300 ºC) for both microstructures prove the initial assumptions and clarify the relative effect of both, temperature and grain size, on the local strain localization.