Suppression of isothermal ω phase by dislocation tangles and grain boundaries in metastable β-type titanium alloys

Aging response of metastable β-type Ti–25Nb–2Mo–4Sn alloys with different pre-treatments was experimentally investigated. Experimental results showed that the precipitation of isothermal ω phase can be suppressed by cold rolling prior to aging. It is considered that the dislocation tangles as well as grain boundaries play a key role in hindering the movements of dislocations necessary for the transition of β to ω. In such a case, suppressing isothermal ω and promoting fine α were achieved simultaneously during aging.

► The aging products of Ti-2524 alloy could be (β + ω) or (β + α), even under the same aging treatment condition.
► ω precipitates can be suppressed by dislocation tangles introduced by cold rolling prior to aging.
► Suppressing detrimental ω and promoting fine α were achieved simultaneously during aging.