Properties and Applications of Ti: Current Status and Future Needs

摘要

This paper examines a variety of applications for all types of Titanium and Titanium Alloys (for convenience Titanium and Titanium Alloys will be referred to hereafter as Ti). These range from traditional applications in aerospace products to growing application areas such as biomedical and dental products, and some attractive, but largely unrealized, applications including automobiles, consumer goods and architecturally inspired structures. For some applications, the unique physical and mechanical properties of Ti alloys make their use ideal. For example, the high density-normalized strength of Ti alloys permits creation of lightweight structures. Further, the intrinsic corrosion resistance of Ti makes it suitable in a wide range of chemical environments and provides the basis for biocompatibility of orthopedic implants. Some Ti based alloys exhibit shape memory and super-elastic characteristics that make them attractive for certain medical devices such as stents. In other applications, the use of Ti is potentially attractive but currently limited by cost. For convenience, both current and future Ti applications will be grouped into those that are performance driven and those that are cost limited. Changing product requirements for traditional application areas, e.g. aerospace, have created new application opportunities such as landing gear for large aircraft and fan disks for high thrust commercial engines. These opportunities will be described and the reasons, including properties, for their emergence will be identified. Biomedical applications for Ti, such as hip implants and dental crowns, will be examined on the basis of properties and chemical composition. In other market sectors, such as automotive and consumer products, potential applications currently are limited by cost. Until now, the added cost of Ti alloys has severely limited their use in automobiles, except for racing cars. Continued increases in fuel cost or new mandated fuel economy standards may change this situation. The prospect of lower cost Ti has the potential to transform these opportunities into real market prospects. The cost sensitivity of Ti also will be examined in the context of realization of these markets. In recent years, the cache' of "Titanium" has led to a number of niche applications that have not been cost driven. Among these are sporting goods and laptop computers. The permanency of this trend will be discussed.