Effect of Processing Parameters on Hot Deformation Behaviour and Microstructural Evolution of PM Ti-5553 Alloy at a Moderate-high Strain Rate

摘要

Isothermal compression tests of Ti-5553 (Ti-5Al-5V-5Mo-3Cr) alloy, produced by a fast consolidation approach from blended elemental powder mixture, were performed on a Gleeble ? 3800 thermal-physical simulator to investigate its hot deformation behaviour. The samples were compressed in a wide temperature range from 700 oC to 1150 oC and a moderate-high strain rate of 1 s -1 , with the sample deformation degree of 30%, 50% and 70%, respectively. Flow instability occurred when the deformation temperature was less than 900 oC. Dynamic recovery (DRV) accompanied by dynamic recrystallization (DRX) become the dominated mechanisms at the medium temperature range between 900 oC and 1000 oC, while almost only DRV features could be observed at high temperature (1050 oC ~ 1150 oC). Moreover, α phase globalization could be identified in the alloy deformed in (α+β) region. DRV, DRX, α globalization and the transformation of α to β phase were promoted with the increasing deformation degree.