E. Y. Chen, D. R. Bice, Transition45 Technologies, Inc., Orange, CA; L. W. Weihmuller, W. A. Thomas, G. D. Hall, Bell Helicopter Textron, Hurst, TX
It is well established that military aircraft systems would benefit greatly from the development and application of high strength, lightweight titanium alloys with improved durability and damage tolerance. Naval aircraft have requirements for such alloys for current and next generation airframes, particularly if they can be used in the cast form for affordability. For certain classes of airframe components, it well established that the potential cost savings can be significant if they were converted from a machined forging to a machined Ti-6Al-4V investment casting. The primary purpose of applying a higher strength-low weight titanium alloy versus Ti-6Al-4V would be to allow direct conversion of these forged components to titanium castings without sacrificing strength or increasing weight. This potential weight saving is especially advantageous for rotorcraft. This study evaluates the high strength, lightweight titanium alloys Ti-6Al-2Sn-2Zr-2Mo-2Cr (Ti-6-22-22) and Ti-5Al-5Mo-5V-3Cr-0.5Fe (Ti-5553) as castings. The castability of these alloys as compared to Ti-6Al-4V will be investigated, as well as their microstructure-properties including tensile and fatigue behavior. A comparison of the mechanical properties of these cast alloys versus those of their wrought counterparts will also be made and these results will be discussed in light of potential applicability to naval airframe structures.
Summary: Naval aircraft have requirements for high strength titanium alloys for current and next generation airframes, particularly if they can be used in the cast form for affordability. This study evaluates the high strength, lightweight titanium alloys Ti-6Al-2Sn-2Zr-2Mo-2Cr (Ti-6-22-22) and Ti-5Al-5Mo-5V-3Cr-0.5Fe (Ti-5553) as castings. The castability of these alloys as compared to Ti-6Al-4V are investigated, as well as their microstructure-properties including tensile and fatigue behavior. A comparison of the mechanical properties of these cast alloys versus those of their wrought counterparts will also be made and these results will be discussed in light of potential applicability to naval airframe structures.
