Evaluation and Modelling of the Residual Stresses Generated on Functionally Graded Materials -Two examples-

1. ABSTRACT A parametric study was carried out to determine the influence of the compositional gradient on the residual stress distribution. The calculations were based on a cylindrical geometry for WC/Co samples and a rectangular geometry for CuNi samples with stepwise compositional variation at the interlayers. The effects of the gradation size and composition profile of the graded materials were investigated by a visco-elasto-plastic finite element analysis using the ABAQUS code. It was found that the degree of residual stress is mostly determined by the compositional distribution and its thickness, but not by the thermal history. The calculated stress values were compared with those measured experimentally either by X- ray diffraction on graded WC/Co specimens or by deflection measurements during electrochemical removal of subsequent layers for graded CuNi samples. The comparison with experimental methods showed good agreement, thus validating the results obtained by the parametric finite element study.