Brazing residual stresses in Glidcop-Al12SiBe

Abstract

Brazing of Glidcop to beryllium by using Al12Si has been considered. Brazinng residual stresses have been determined by a finite element method. Temperature-dependent elastic properties and coefficients of thermal expansion have been used. Plastic deformation of the brazing alloy, based on experimental stress-strain curves for Al12Si at different temperatures, has been included in the FEM analysis. It has been shown that the plastic deformation of the brazing layer, even if only 50 μm thick, affects the residual stresses considerably. In general, a decrease of the residual stresses with increased Al12Si layer thickness has been observed. Successful brazing may require a thickness of 500 μm or larger. The calculated residual stresses are produced as a result of the brazing operation because of the thermal expansion mismatch of the adherend materials. The effects of the subsequent service conditions such as mechanical loading, thermal gradients, and neutron irradiation on the material properties and the residual brazing stresses have not been considered in this paper.