Abstract
The present paper is an analysis of the results from a finite element method (FEM) study of the mechanical behaviour and state of stresses developed during the tensile testing of AISI 4130 steel–Incoloy 825 bimetallic composite specimens. The geometries of the specimens simulated are identical to those tested and machined from a commercial bimetallic tube heat treated under several conditions. The resulting microstructures have also been analysed. The FEM analysis shows that before necking, the rule of mixtures correctly predicts the flow behaviour of the bimetallic composite. After necking, stresses normal to the interface are developed. Shear stresses at 45° seem to be responsible for the formation of initial intergranular cracks along a zone of high density carbides precipitated inside the Incoloy 825. The normal stresses finally cause fracture of the composite along this region of carbides.
MST/3089
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