Friction surfacing on nonferrous substrates: a feasibility study

This work reports a feasibility study on producing friction surfaced coatings on nonferrous substrates. Commercially pure aluminum, copper, magnesium (ZM21), Inconel 800, and titanium alloy (Ti-6Al-4 V) were chosen as the substrates. Low carbon steel, aluminum alloy (AA6063), commercially pure copper and titanium were chosen as the consumable rods. Friction surfacing was attempted with all consumable rods on every substrate. In some cases metallurgically bonded coating was obtained readily over the substrate and in some other cases coating was obtained with a start-up plate. However, for certain combination of parameters, no coating could be obtained. The coatings obtained were analyzed for their microstructural features and interfacial characteristics using optical and scanning electron microscopy. The results showed that co-efficient of friction, material properties like thermal conductivity, and stability at high temperature influenced the formation of a coating. Coatings obtained exhibited fine grained microstructure with properties better than the original parent material. Dynamic recrystalization as a result of severe plastic deformation accounts for grain refinement.