The present investigation demonstrates the process parameters optimization for obtaining high weld strength in cold solid state joining of dissimilar powder metallurgical (P/M) preforms. In the cold pressure welding of two dissimilar P/M preforms, to ensure a sound weld, the mechanism of bonding is illustrated to be influenced by volume ratios of the two materials, the amount of plastic deformation and the interfacial area. The Taguchi method is used to analyze the individual effect of each process parameter and their interaction, on the quality characteristic, viz., weld strength, and subsequently to determine the process parameters with the better weld strength. The results revealed that the volume ratio of copper to steel had strong influence on the weld strength of the preforms joined with and without the interlayer, when compared to density ratio (steel to copper). However, the interaction of volume ratio and density ratio was found to affect the weld strength in both the cases. In the joints made with interlayers, the density ratio also played an important role in determining the weld strength. The interlayers were found to increase the weld strength by approximately 36 percent. Further increase in the weld strength can be realized by reducing the thickness of the interlayer and the particle size of the interlayer powder.
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