Novel Titanium Manganese Alloys and Their Macroporous Foams for Biomedical Applications Prepared by Field Assisted Sintering

In this chapter, a novel titanium (Ti) alloy and foam suitable for biomedical applications will be introduced. As we know, Ti and its alloys are widely used as biomaterials especially for orthopedic implants in load bearing sites as dental and orthopedic implants and heart valves, due to their high mechanical properties, corrosion resistance and biocompatibility (Geetha et al., 2009). Pure Ti was once used as biomaterial, but its disadvantage as implant materials is low strength and insufficient hardness. Therefore, the Ti6Al4V alloy is preferentially in clinical use because of its favourable mechanical properties. However, some studies showed that the vanadium (V) and aluminium (Al) release in Ti6Al4V alloy could induce Alzheimer’s disease, allergic reaction and neurological disorders (Mark & Waqar, 2007). Therefore, the exploration of high strength new Ti alloys without Al and V for medical implants has gained great attention in the past years and it is still ongoing. Al and V free alloys containing non-toxic elements such as iron (Fe), niobium (Nb), zirconium (Zr), tantalum (Ta), molybdenum (Mo), nickel (Ni), gold (Au), or silicon (Si), etc. were investigated (Zhang, Weidmann et al, 2010). As long-term load-bearing implants in clinic, the incorporation of porous structures into the Ti and its alloys could lead to a reliable anchoring of host tissue into the porous structure, and allow mechanical interlocking between bone and implant (Li et al, 2005). The porous structure is preferable for Ti and its alloys used as bone implants. Many techniques have been applied to produce Ti foams in recent years. Nevertheless, there are still problems to be solved in the field of Ti foams for biomedical applications (Zhang, Otterstein et al., 2010): the difficulty to create controlled porosity and pore sizes, the insufficient knowledge of porous structure-property relationships, the requirements of new sintering techniques with rapid energy transfer and less energy consumption and so on. The Ti alloys and foams are difficult to be produced from the liquid state due to high melting point, high reactive activity at high temperature above 1000 oC and contamination susceptibility. The production of Ti alloys and foams via a powder metallurgy (PM) route is attractive due to the ability to produce net-shaped components. Because of their stable