Titanium Alloy Development Needs for Commercial Airframes: An Update

There is increasing pressure on the aircraft industry to reduce both manufacturing and operating costs. The former occurs in the form of pressure to reduce component and material costs; the latter in the form of reduced maintenance costs and aircraft weight. Weight and cost are thus interrelated, and sometimes at odds, in the design process.

Titanium is historically utilized in airframes to solve specific problems related to high temperatures, specific strength or corrosion. For graphite-reinforced composite airframe structures, the natural compatibility of titanium has lead to an increase in the fraction of titanium alloys on the airframe, but with concordant increases in build costs. Titanium is galvanically compatible with the graphite in the graphite-reinforced composite, and the coefficient of thermal expansion of titanium is closer to graphite than to aluminum or steel. This has lead to an evolution in the needs of the airframe industry with respect to titanium alloy properties and utilization.

This paper will provide an overview of cost reduction opportunities, typical airframe applications and design drivers for titanium alloys. The purpose of this paper is to relate these needs to the titanium industry so that better alloy development solutions and improved processing methods can be conceived and offered.