Mechanical Characterization and Fracture Toughness of Electroplated Cadmium Coating of Al - Zn Alloy, T6

Fracture toughness, Hardness and Tensile Strength of the Aluminum alloy 7075-T6 coated with Cadmium with varying thickness of 10 mu and 20 mu were investigated. Electroplating Cadmium coating process gives excellent corrosion resistance, provides low coefficient of friction which increases the surface hardness of the material. It also provides a uniform and dense coating, in many cases, maintains surface finish as it was before plating. The specimens prepared in line with ASTM E-8M and E-399 standard were subjected to various tests. The results shows that the hardness of the EC coted specimens has increased by 10% and increases with increase in thickness, butthe thicker the EC coating, more brittle is the material. The Ultimate Tensile Strength also increased by 5% compared to the uncoated counterpart. There was a steep increase in plain strain fracture toughness with the increase in the coating thickness for the Aluminum 7075-T6 alloy in TL orientation. The crack growth was Unstable due to the strong adhesion between the EC coating and the alloy.