Tensile Failure Monitoring of Zirconium Alloy Micro-arc Oxidation CoatingBased on Acoustic Emission Technology

The micro-arc oxidation coating was prepared on the surface of zirconium alloy substrate by the constant pressure micro-arc oxidation equipment. The tensile process of the coating sample was monitored in real time by acoustic emission technology. The tensile failure process of the coating sample was studied by analysis of acoustic emission characteristic parameters and observation of tensile fracture morphology, and the frequency characteristics of the coating tensile failure were identified by fast Fourier transform. The results show that micro-arc oxidation coating mainly affected the tensile properties of zirconium alloy at the plastic stage. During the tensile process, the microcracks in the coating randomly extended in all directions, leading to the phenomenon of concentrated peeling of the coating at the plastic stage (132-222 s); the coating was basically detached from the substrate before fracture, and only some irregular coating was scattered in the local area of the fracture. The frequency characteristics of coating tensile failure were three strong signal at 0.023, 0.039, 0.055 MHz, and weak stable signal in the frequency band greater than 0.8 MHz.