Investigation of the effect of alloying elements on the printability of biodegradable material


The integration of biodegradable implant into the human body must meet both engineering and physiological requirements. The properties of magnesium such as low density, high specific strength and other biocompatibility properties makes magnesium and its alloy suitable for several biodegradable implant application. However, the current available magnesium alloys still rely on structural / commercial purpose alloys which are not specific to human body environment, too fast degradation and limited mechanical performance of the alloys. Additive manufacturing seems to have potential effect for magnesium alloy implant performance and production such as design and production of patient-specific implants, geometrically and mechanically adapted to the specific patient yet limited work has been done in this new area. Extensive trial-and error was already shown from previous magnesium alloys implant as implant application.

A way to tackle the burden of undertaking extensive experiment is by using Computational aided alloys design. CALPHAD or CALculation of PHase Diagram is a computational modelling where all available experimental and theoretical information on phase equilibria and thermochemical properties collected into a system database. Further, ICME aims to integrate computational materials science tool into a system which accelerate materials development, design optimization process and unify design/manufacturing and ICME utilized CALPHAD as one of the methods for designing alloys.

Screening possible alloying element was performed than calculation of each element effect was investigated. The effect on mechanical strengthening and possible defect induced by alloying was performed. It was found that the promising composition alloys proposed to be Mg-4Zn-(0.7-1.5 wt.%) Ca-(<1wt.%) Sn and higher solute in single phase will result in higher hot tearing susceptibility index due to increasing liquidus temperature so that freezing range become wider and hinder precipitation which decrease final composition of eutectic phase.