Experimental Study on Cyclic Deformation Behaviour of A7N01-T4 Aluminum Alloy Welded Joint Based on Three Dimensional Digital Image Correlation Method

To investigate the uniaxial tension and cyclic deformation characteristics of A7N01-T4 aluminum alloy welded joint by the method of metal inert gas (MIG) welding, the digital image correlation (DIC) method was used to indicate strain distribution under monotonic tension and cyclic loading, and the averaged stress-strain curves strain of welded joint, weld zone, heat-affected zone and base metal were obtained by combining the observations of micro-hardness. The experimental results show that the plastic deformation of the welded joint under monotonic tension and cyclic loading is mainly dominated by the weld zone and the heat-affected zone since the base metal in welded joint has always been in the state of elastic deformation, and A7N01-T4 aluminum alloy welded joint exhibits cyclic stable feature and ratchetting shakedown state, and the ratcheting strain of the welded joint depends on the current stress level and the loading history.