Tensile behavior of fusion-brazed aluminum alloy coach-peel joints fabricated by a dual-beam laser

As the stress-strain data of the fusion-brazed filler material AA4047 could not be easily or directly measured, an isotropic strain-hardening model of the fusion zone material AA4047 was estimated by an inverse method to quantify the tensile behavior of AA6111-T4 coach-peel joints. The Hill's 1948 quadratic anisotropic yield stress function for the base sheet metal AA6111-T4 was first determined by conducting uniaxial tensile tests on the sheet metal in the rolling, diagonal, and transverse directions. Based on the yield stress function and isotropic strain hardening behavior determined for the base sheet metal, the linear-exponential strain hardening model was used to identify the fusion zone material AA4047 by an iterative correction and image-based finite element analysis of the welded joint. Modeling of joints with and without flawed brazing interface showed that the load-carrying capacity of coach-peel joints was insensitive to the existence of the brazing zone metal AA4047. When the fusion zone model was also applied to the brazing zone, the predicted and measured force-displacement curves of the coach-peel joint matched well. The failure stress of the coach-peel joint was identified as the von Mises fracture stress of 100 MPa at the brazing interface.