Promoting nano/ultrafine-duplex structure via accelerated α precipitation in a β-type titanium alloy severely deformed by high-pressure torsion

The introduction of severe plastic deformation by high-pressure torsion greatly altered the ageing response of a Ti–20 wt.% Mo β alloy, promoting equiaxed (instead of acicular) α precipitation to form a complete ultrafine-duplex (α + β) structure when subjected to sufficiently high strain. Three prominent features, namely abundant grain boundaries, enhanced atomic transport and nanoscale β matrix grains, were recognized as decisive factors contributing to such unusual precipitation behaviour.