Multiple deformation mechanisms induce high work hardening in Ti–5Al–7.5 V alloy via transformed β matrix

Abstract

In this work, different transformed β matrix was obtained in Ti–5Al–7.5 V alloy. The alloy with equiaxed αp phase and transformed β matrix containing α′ martensite and β phase exhibits good combination of strength and plasticity, as well as a high work hardening rate. A concurrent operation of stress-induced α″ martensitic transformation, deformation twinning and dislocation slips was observed governing the deformation process of this alloy. The alloy with equiaxed αp phase and transformed β matrix containing secondary αs plates and retained β phase shows a high strength and plasticity but low work hardening rate, which is caused by dislocation slips.HighlightsThe quenched Ti–5Al–7.5 V alloy exhibits a high work hardening rate, approximately 5500 MPa.The dependence of work hardening rate of Ti–5Al–7.5 V alloy on transformed β matrix is revealed.Concurrent operations of stress-induced α″ martensitic transformation, deformation twinning and dislocation slips govern deformation of the studied alloy.

Keywords

• Titanium alloys
• work hardening
• martensitic phase transformation
• twinning
• dislocation slips