Multi-scale modeling for prediction of mechanical performance in brazed GH99 thin-walled structure

Abstract

Superalloy thin-walled structures are achieved mainly by brazing, but the deformation process of brazed joints is non-uniform, making it a challenging research task. This paper records a thorough investigation of the effect of brazing parameters on the microstructure of joints and its mechanical properties, which mainly inquires into the deformation and fracture mechanisms in the shearing process of GH99/BNi-5a/GH99 joints. The macroscopic-microscopic deformation mechanism of the brazing interface during shearing was studied by Crystal Plasticity (CP) and Molecular Dynamics (MD) on the basis of the optimal brazing parameters. The experimental results show that the brazing interface is mainly formed by (Ni, Cr, Co) (s, s) and possesses a shear strength of approximately 546 MPa. The shearing fracture of the brazed joint occurs along the brazing seam, displaying the characteristics of intergranular fracture. MD simulations show that dislocations disassociate and transform into fine twinning with increased strain. CP simulated the shear deformation process of the brazed joint. The multiscale simulation results are consistent with the experimental results. The mechanical properties of thin-walled materials for brazing are predicted using MD and CP methods.