Low-cycle fatigue lifetime estimation of Ti–6Al–4V welded joints by a continuum damage mechanics model

The low-cycle fatigue(LCF)behavior of directionally solidified nickel-based superalloy Ti–6Al–4V was studied under bare and electron beam welding conditions at room temperature.Results show that:(1)under the same test conditions,all the joints exhibit lower LCF lifetime than Ti–6Al–4V;(2)the failure of welded structures is mainly ascribed to the welding defect.A novel lifetime prediction methodology based on continuum damage mechanics is proposed to predict the lifetime of Ti–6Al–4V and its welded joints.