基于数字图像相关法的A7N01-T4铝合金焊接接头循环变形行为实验研究

为研究A7N01铝合金MIG焊焊接接头单轴拉伸性能和循环变形特征，采用数字图像相关方法(DIC)分析A7N01铝合金焊接接头在单调拉伸和循环加载下的应变场分布，结合焊接接头显微硬度获取焊接接头整体、焊缝、热影响区和母材的平均应力-应变曲线。实验结果表明:焊接接头母材在单调拉伸和循环变形中一直处于弹性变形，焊接接头整体的塑性变形由焊缝和热影响区主导，体现出循环稳定特征和棘轮安定状态，焊接接头的棘轮应变值依赖于当前的应力水平和加载历史。

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.