Impact of 3D-printed PLA coatings on the mechanical and adhesion properties of AM60 magnesium alloys

This article investigates the impact of PLA (Polylactic Acid), an emerging bioplastic coating, fabricated with an additive manufacturing method (3D printing) on AM60 magnesium alloys. In addition to tensile testing, the adhesion of PLA on magnesium alloys with two epoxy and polyvinyl pyrrolidone adhesives was checked with the pull-off experiment. The strength of the bond between PLA and AM60 magnesium alloy was tested using two different adhesives, polyvinyl pyrrolidone and epoxy glue. The polyvinyl pyrrolidone adhesive resulted in an adhesion strength of 0.3 +/- 0.02 MPa, whereas the epoxy glue resulted in a much stronger adhesion strength of 4.29 +/- 0.71. Coating the AM60 magnesium alloy with PLA led to enhancements of 5.26 % in the yield stress (Syt), 7.79 % in the ultimate stress (Sut), 2.40 % in the elongation, and 2.34 % in the elastic module, as compared to the uncoated specimen. The fracture surface was also checked with FESEM (field-emission scanning electron microscopy) images. It was found that the fracture type for AM60 magnesium alloys with and without PLA coatings was brittle under tensile loading.