Nanostructured Biomaterials for Load-Bearing Applications

Abstract

Biomaterials with appropriate mechanical properties, high biocompatibility and bioactivity are selected for load-bearing implant materials. Grain size is well known to have a profound effect on the mechanical behavior of materials, in particular, on the strength characteristics. As bone is a complex nanostructured composite material, mimicking biomaterials at the nanoscale level will enhance its mechanical and biological properties in load-bearing sites. The most common metals and alloys used as biomaterials for load-bearing applications include titanium and its alloys, Co–Cr alloys and stainless steel. However, titanium and its alloys are most widely preferred over other materials for possessing excellent properties. One of the methods to improve mechanical strength is grain refinement. Severe plastic deformation (SPD) techniques are used to obtain ultrafine grain (UFG)/ nanostructured refinement in titanium and its alloys. These SPD techniques will not only enhance the mechanical properties of cp-Ti but also increase the osteointegration and bioactivity of the implants. This chapter describes various SPD techniques (equal channel angular pressing, repetitive corrugation and straightening, high-pressure torsion, accumulative roll bonding, ball milling, etc.), characterization and process parameters to achieve UFG/nanostructured refinement along with the advantages and disadvantages.