Effects of the number of equal-channel angular pressing passes on the anisotropy of ultra-fine titanium

Annealed commercially pure titanium was processed by four passes of equal-channel angular pressing at a temperature of 450 °C using route BC. Pressed samples had a square section with a side length of 8 mm. Anisotropy was analyzed based on the conventional yield strength at compression in three mutually perpendicular directions. Compression tests were performed with static loading at room temperature and at 450 °C. The tests were conducted with the as-received material, and after 1, 2, 3 and 4 passes. Anisotropy of the as-received condition holds out at further pressing and makes about 25%. Anisotropy after all the passes is similar both for room and elevated temperature.Anisotropy characteristics are observed to change during the third pass. The anomalous change in anisotropy during the third pass is also evidenced by the analysis of microhardness measurements in different section planes of the samples.