Residual stress analysis in titanium alloys used for biomedical application

Abstract

Biomedical applications like cranial plate, knee arthroplasty, ankle replacement, elbow and knee support braces, other orthopedic implants, and braces are required to be customized depending on the respective human body. These items can be made up of sheet metal. The slightest modification to the overall shape of sheet metal components leads to a reduction in production rate, raises costs, and impairs dimensional accuracy. Commercially pure titanium due to its excellent corrosion resistance, high formability properties, and high strength-to-weight ratio is considered to be an excellent material for a medical prosthesis. Single point incremental forming (SPIF), is an emerging technology that consists of a basic hemispherical tool, numerically monitored by a CNC machine that performs a progressing highly localized deformation. The poor dimensional accuracy would attribute to the development of residual stresses which may cause severe conditions for cranioplasty patients if the cranial plate is deformed. Even a small deformation due to residual stress may result in surgical replacement or even severe pain. Therefore, a better knowledge of the residual stresses is necessary to improve the geometrical precision of the process. The primary field of study is to thoroughly examine the surface residual stresses affected by the different process parameters of single-point incremental forming. In addition, microstructural behavior and forces induced during SPIF were also observed in relation to the strength of sheet metal.