Numerical analysis of drilling AZ91 magnesium foam.

Novel AZ91 magnesium syntactic foams are a potential choice for temporary biomedical implants. In many cases, holes of various sizes need to be machined on the biomedical temporary implants using the drilling process to facilitate placement of implants inside the human body. In this study, the drilling performance of AZ91-magnesium foam is investigated under different lubrication methods such as dry, wet (Almag® mineral Oil-wet machining), and cryogenic cooling. Drilling experiments were carried out using coated and uncoated titanium aluminium nitride (TiAlN) twist drills on varying volume fractions of AZ91 magnesium syntactic foams (5%, 10%, and 15%) reinforced with hollow alumina microspheres. A three-dimensional, thermo-mechanical finite element-based model for drilling magnesium syntactic foam using AdvantEdgeTM is presented for different lubrication conditions. The numerically predicted machining induced stress from the finite element model showed a compressive stress give a better surface integrity and quality to the machined surface in liquid nitrogen coolant when compared to dry machining. This shows cutting with cryogenic cooling as a sustainable drilling process for AZ91-magnesium syntactic foams. [ABSTRACT FROM AUTHOR]