[T5] Field Assisted Sintering Technologies

[16B-T5-04] Understanding the Influence of Thermal Gradients during Large-Scale FAST/SPS on Final Microstructure after Secondary Hot Rolling of Ti-5553

*S. Lister¹, J. Pepper¹, W. Pulfrey¹, M. Jackson¹ (1.University of Sheffield, UK)

Keywords:FAST, SPS, Titanium

As Field Assisted Sintering Technology (FAST) matures, a greater focus is being placed on the production of larger samples. The challenges presented by thermal gradients within larger parts are well documented, e.g. subsequent heterogeneity in grain size and mechanical properties. Several methods to reduce such thermal gradients have been developed but often require more complex and costly tooling design. However, the influence of initial grain size heterogeneity on the final part properties after secondary thermomechanical processing is currently unknown. Here, we apply hot rolling to a Ti-5553 billet processed with an intentionally large thermal gradient during FAST. Analysis of grain size, microstructure and hardness was performed at multiple locations in the as-FAST, FAST + rolled and FAST + rolled + HT conditions. These results provide an understanding of the importance of controlling thermal gradients in titanium alloy FAST/SPS parts prior to secondary thermomechanical processing operations.