Formability Assessment with Microstructural Investigations for Zirconium 702 Thin Foils: Bio-Material Applications

Abstract

ABSTRACT Application of Zirconium alloys for biomedical applications have received increasing attention. Unique properties like formation of an internal bone-like apatite layer and also the interaction with magnetic resonance imaging (MRI) diagnostics with better compatibility, low magnetic susceptibility and overall excellent biocompatibility, mechanical properties and resistance to biocorrosion. Forming process is plastic deformation process wherein material undergoes permanent deformation in die cavity without fracture. Local necking, wrinkling, cracking, earing etc are few of observed errors. Due to miniaturization, manufacturing at micro level is essential. Micro forming is difficult to control as thickness of foil is below 100 microns. Hence, investigation and prediction of mechanical properties of the material at micro-level plays a very vital role. The current research focusses on the forming limit curves (FLC), which is one of the way of investigation performed to predict the formability of the material Zirconium 702 (Zr702) with the sheet thickness 100 microns. Nakajima test as per the ASTM 2218–14 standards was applied. Numerical and Experimental FLCs arrived at shows good concordance. Micro-structural study is also performed on the test specimen before and after forming to analyse the behaviour of the material.