Effect of peening based processes on tribological and mechanical behavior of bio-implant materials

Abstract

Abstract Implant materials are those implanted in human body, which are required to replace the diseased organ without causing any toxicity to human environment and sustain for longer period of time. As the implant materials are subjected to various stresses and cells in the human also requires an appropriate stresses to differentiate, the mechanical properties of an implant under different loading conditions, play an important role in determining the performance of the implanted material. Various properties such as wear resistance, tensile strength, fracture toughness, and modulus of elasticity would determine the applicability of a particular implant material for replacement in case of hip and knee joint replacement and fractured bone joints. The implants, plates, and screws are made of materials such as 316 stainless steel cobalt–chromium alloy and titanium alloys. As surface of an implant are subjected to wear, corrosion, and bone integration, the failure of the implants are initiated on the surface and hence a number of surface modification processes and thermo-mechanical/chemical treatments are carried out on these materials to achieve the desired properties. Various surface modification techniques such as plasma spraying, physical vapor deposition, and chemical vapor deposition are carried out coat wear and corrosion resistance ceramics. Few surface modifications such as sand blasting, etching, surface mechanical attrition treatment (SMAT), and peening are used to modify the surface without the addition of coatings. In this chapter the influence of peening on various biomaterials is elaborated. The enhancement of tribological and mechanical properties by virtue of peening and the corresponding mathematical relationships which correlate the changes are presented. The outcome of this chapter is intended to accelerate research in this isolated and upcoming area of peening which is generally performed on various aerospace and automotive materials for improving their fatigue/endurance limits in real time applications.