Numerical Optimization and Practical Implementation of the Tube Extrusion Process of Mg Alloys with Micromechanical Analysis of the Final Product

Abstract

The paper is devoted to the development of a process of tubes extrusion from MgCa08 magnesium alloy. For optimization of extrusion process the Qform software was used. The numerical model of flow stress and fracture criterion for MgCa08 were obtained based on tension/compression measurements performed in a universal testing machine Zwick Z250. Predictions of the flow stress and deformations were modeled as well as the ductility of material. The process was optimized according to the plasticity and temperature criterions. In the optimization process, temperature of the billet and the speed of extrusion were determined. Based on the optimal parameters the extrusion of tubes with external diameter of 5 mm was performed in the laboratory press. On top of the macroscopic testing and calculations, investigations of the material microstructure and the micromechanical behavior of the material after the extrusion were performed by a combination of SEM and nanoindentation analyses. Micromechanical properties of the alloy were detected with the aid of statistical nanoindentation. Samples were characterized in terms of their microstructural defects, distribution of elastic modulus and hardness. Good particle dispersion and homogeneous-like distribution of micromechanical properties was found showing the efficiency of the extrusion process.