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.