Simulation of the High Strain Rate Deformation Behavior of Titanium Based Alloy for Biomedical Applications

Abstract

Human body functions as a network of mechanically coupled parts (components) that work together to form a complete system; these body components can experience failure when in service. Specifically, failure such as arthritis may be caused by articulations at the hip and knee joints. One of such solutions to this failure is the total hip replacement. Materials used in this prosthesis, therefore play an important role in the success of the implant. One of the most commonly used implant material in modern day arthroplasty is the Ti6Al4V alloy, because of its excellent resistance to wear and corrosion in the human body environment. In reality, such implant in service may be subjected to impact loading (at a velocity of about 250–1000m/s), leading to deformation. Typical, examples include an implanted patient involved in an automobile crash and a golf ball hitting an implanted patient at the point of implantation. In this study, the wear and tear resistance property of Ti6Al4V alloy is determined by performing simulation on the high strain rate deformation behavior of IN718 super alloy material and Ti6Al4V plated Inconel material. The maximum stress localized within the plated Inconel material is lesser than that in the unplated material. This shows that Ti6Al4V alloy prevents the localization of stress in the parent Inconel material and is therefore a good wear prevention material, under impact conditions. Also, the impact characterization behavior of Ti6Al4V material is performed in this research in order to determine the maximum stress allowable in the titanium alloy before ultimate failure. Simulation of the high strain rate behavior of the Ti6Al4V alloy is performed at velocities in the range 9–20m/s. It is observed that the localized stress within the Ti6Al4V alloy increases with increased impact velocity. A maximum localized stress is observed in the material beyond which the Ti6Al4V alloy experiences failure. The result of the simulation process helps in determining the maximum impact which an implanted patient can therefore be exposed to and the preventive measures that can be taken in order to guarantee safety of the implanted patient.