Aerospace functional alloys for stiffness and wear resistance

Aerospace and space industry has been traditionally known for development and introduction of latest material systems and development techniques. The main driving factors for materials development are weight loss, application oriented function enhancement and decreased costs. Application of latest engineering materials has wide impact on both economical and ecological problems.

Aluminum alloys basically cover cryogenic and moderate high temperature range applications. Material strengtheners are used where high stiffness and wear resistance are needed. Titanium alloys are used in the temperature limit of about 500 to 550oC.

Aerospace industry always demands for the advanced materials for challenging performance needs of a component that is often a integral part of a complex technical system. The major issues to be fixed by advanced material development are material characteristics, fabrication and costs. Component performance in this sector is basically determined by mechanical characteristics for example strength, stiffness and damage tolerance and physical and chemical characteristics like density, corrosion resistance at ambient and high temperatures. Using suitable development methods have a special role with regard to material properties and costs and may hence eventually determine whether an advanced material will find application. Nowadays life cycle costing has been referred as an essential tool to determine the economic feasibility of the material.

The major driving forces for engineering materials development in aerospace and space industry are weight loss and high temperature capability. Weight loss is effectively done by decreasing density. Additionally weight loss of a specific component can develop a snowball effect if the airframe and engine of aircraft allow using less stringers, a downsized engine, small wing and more. For aircraft, similar benefits related with a loss of fuel consumption are achieved by improving the efficiency of engines through higher turbine inlet temperatures. However a large count of additional criteria is stressed for every application, materials are usually categorized according to their properties. Aluminum and titanium based alloys are the recommended lightweight aerospace alloys.

Aluminum alloys are utilized at room temperature and in cryogenic applications, enhancing the high temperature properties and the corrosion resistance of these alloys. Titanium alloys are used when lighter weight aluminum alloys do not fit in the needs of strength, corrosion resistance and high temperature needs. For use at temperatures of about 800oC Nickel base alloy Inconel 718 wire are used as the prime materials in aeroengines in a condition where high temperature capability and high strength are needed. Single crystal turbine blades show state-of-art technology. Besides of their use in high temperature applications, they are continuously finding new applications in structural parts.

Normally the material characteristics can be tailored to the required component application by change in processing. Certainly no other metal is more closely connected with aerospace industry than titanium. Titanium alloys offer supreme corrosion resistance and excellent strength to weight ratio. In addition of strong efforts to increase the part in general industrial market the largest part of produced titanium still goes into aerospace industry.