Numerial model of warm drawing of the biocomptible MG alloys accounting for ductility of the material

Abstract

Due to high compatibility and solubility in human organism, special magnesium alloys are applied in bioengineering. Production of surgical threads to integration of tissue can be application of these types of alloys. This sort of application calls for fine wires with diameters from 0.1 to 0.9 mm. The warm drawing process in heated dies was proposed to increase the workability of the Mg alloys. The purpose of this paper is development and experimental validation of a mathematical model of a warm drawing process of wires made of MgCa0.8, Ax30 and ZEK100 alloys and determination of optimal parameters with the objective function defined as maximum of workability. The first part of investigation is focused on development of a numerical model, which is based on FE solution. The second part of paper is focused on experimental upsetting and tensile tests. Basing on these tests the flow stress and fracture models were obtained. The materials models are implemented into the Authors’ FE code, which is dedicated to modelling of drawing processes. For experimental verification of model the thermo visual analysis of wire drawing and tests of mechanical properties of wire were performed. With help of model the dependence between technological parameters of drawing and ductility function was obtained. The technical problem defined as determination of optimal drawing velocity, which is helpful to obtain the temperature in deformation zone taking into account fracture criterion, was solved. The optimum drawing schedule for Mg alloys was proposed.