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

In the present study, the effect of cold rolling and subsequent annealing on the microstructure and mechanical properties of metastable β Ti-10V-2Fe-3Al (Ti-1023) and Ti-5Al-5Mo-5V-3Cr (Ti-5553) alloys have been investigated. Room temperature cold rolling have been conducted on the alloys (5 mm3 samples). A thickness reduction up to 43% and 45%, respectively for Ti-1023 and Ti-5553 have been achieved. Subsequent annealing treatment in single β phase regime have been considered to effectively control the grain size in both Ti-1023 and Ti-5553 alloys. The annealed microstructures have been analysed for their β grain size using a combination of optical microscopy and SEM tools along with ImageJ package. Grain sizes in the range of 45 to 125 µm and 58 to 130 µm, respectively for Ti-1023 and Ti-5553 have been achieved. The β grain orientations have been obtained using FESEM-EBSD tool. A nanoindentation study on the various grain size and grain orientations of the retained β phase was carried out. The alloys showed stress-induced martensitic (SIM) transformation. The triggering stress for this transformation have been measured at room temperature. A clear influence of β grain size and grain orientations on the SIM transformation have been obtained. As well an understanding on the favourable grain orientations for SIM have been obtained. (100), (101), and (111) orientations have been considered for the SIM study.