Specimen size for obtaining joint strength of dissimilar materials subjected to tension has been investigated by using numerical method and experiment. Stress distributions along the bond are calculated by the Finite element method with 8-node distorted element. It was shown that both the residual stress produced by changing temperature and the stress produced by load were dominated by similar law. Tensile test of diffusion bonded joint of dissimilar materials of Ti and Cu was done. The following conclusion is obtained; When the length of tensile specimen is longer than 8 times of diameter of round bar, specimen size does not affect the tensile strength.
