The Effect of Irradiation of a Titanium Alloy of the Ti–6Al–4V–Н System with Pulsed Electron Beams on Its Creep

Abstract

Comparative studies of the effect of pulsed electron beam irradiation of the Ti–6Al–4V titanium alloys with the contents of hydrogen of 0.002 wt.% (VT6 alloy) and 0.23 wt.% (VT6–0.23H alloy) on their structure and peculiar creep behavior are performed at a temperature of 723 K within the range of creep rates 10–7–10–5 s–1. It is found out that irradiation of the VT6 and VT6–0.23H alloy samples with electron beams in the no-melting mode neither changes nor increases their steady-state creep. It is shown that formation of a modified surface layer during electron beam irradiation in the melting mode gives rise to a decrease in the steady-state creep rate in the VT6 alloy and its increase in the VT6–0.23H alloy. It is demonstrated that the dependence of the steady-state creep of the VT6 alloy on the stress before and after pulsed electron beam irradiation is satisfactorily described by the creep power law. The presence of hydrogen in a solid solution in the VT6–0.23H alloy violates the creep power law. The physical causes for the high values of a stress sensitivity index and an effective creep activation energy of the VT6 and VT6–0.23H alloys are discussed.