Micro-scaled plastic deformation behavior of biodegradable AZ80 magnesium alloy: experimental and numerical investigation

Abstract

Microforming is a promising technology in manufacturing micro parts through plastic deformation. In manufacturing of micro part, grain size and material behavior plays a very important role in material flow, yield strength, surface roughness, and microhardness of the micro part. In this work, a generic microextrusion tooling system is developed and biodegradable AZ80 magnesium with four different grain sizes is experimented to analyze the material behavior and grain size effect based on the punch force, microhardness, and interfacial friction. It is attempted to minimize the interfacial friction using two different die coatings. It is found that size, boundary, and distribution of grains have severe effect in the microextrusion process. Microhardness values at the surface layer and radial location show an adverse effect on overall hardness distribution of the micro part due to inhomogeneous deformation. The quantitative variation in interfacial friction is determined with different friction coefficient by numerical evaluation. This research provides the fundamental understanding about the microextrusion process on AZ80 magnesium and facilitates the development of microimplant.