Impact of out‐of‐plane constraint on creep crack growth behavior of M174+ aluminum alloys by nano‐computed tomography (CT)

Abstract Nano‐computed tomography (nano‐CT) was utilized to assess the three‐dimensional information on inner damage and reveal the impact and mechanism of out‐of‐plane constraint on creep crack growth (CCG). Experimental findings revealed that stress levels (C* value) altered the impact and mechanism of out‐of‐plane constraint levels on CCG rates. In the lower C* region related to actual serving conditions, the increase in the level of out‐of‐plane constraint accelerated the CCG rates, which could be attributed to a change in the creep fracture mode from creep ductile fracture to creep brittle fracture. Elevated stress levels enlarge the creep deformation and plastic deformation as well as promote the coalescence of holes and propagation of creep cracks, thereby increasing the CCG rates.