Tensile fracture behaviour of Cu- and Ni/Cu-coated Mg alloy (AZ61)

The tensile fracture behaviour of alkaline Cu-, acidic Cu-, and Ni/Cu-coated AZ61 specimens was studied. Experimental results show that the tensile behaviour of an AZ 61 specimen is similar after alkaline Cu electroplating and Ni/Cu electroplating with a Ni thickness of 3 mu m. In contrast, the elongation percentage for an AZ61 specimen clearly decreased after acidic Cu-electroplating and Ni/Cu electroplating with a Ni thickness of 15 mu m. By observing the fracture surface of coated AZ61 specimens with lower elongation percentages, cracks can be initiated from the Cu deposit into the AZ61 substrate, forming a cracking plateau. However, cracking of the Cu-deposited AZ61 specimen can be hindered by electroplating a Ni deposit. The cracking of uncoated and coated AZ61 specimens during and after a tensile test was discussed. (c) 2012 Elsevier B.V. All rights reserved.