The objective of the technical effort is to eventually identify a material and a process that produces thin wall high pressure tubing for high performance aircraft, specifically Navy aircraft. The need for improvements stems from disastrous failures and the subsequent failure investigations that have indicated a need for a more fracture-tolerant tubing material. The first phase of the effort will consist of four distinct activities: 1. Titanium Alloy, TI-425.will be evaluated as a replacement material for Ti-325, the alloy used in current high pressure hydraulic tubes. The former is a relatively new alloy, stronger than Ti-325, with good cold-working performance. This activity will use flat plates. The goal is to identify an oxygen level and thermal treatment that results in a condition such that the 425 alloy is still stronger (and more crack resistant) than the 325 alloy while, exhibiting superior ductility ( and thus, workability). 2. Manufacturing studies will be conducted with major Titanium suppliers to insure that the research results can be economically transferred to large-scale industrial practice 3. Systems-level studies will be held with a major aircraft manufacturer to determine the impact of the change in tubing material on systems performance. 4. Liasion will be established with laboratories involved in Pressure Impulse Testing
Benefit: The immediate beneficiary of this activity is NAVAIR. The probability of a disasterous, deadly and unnecessary rupture of a high pressure hydraulic line will be reduced. Navy personnel will not be subjected to danger from their own equipment. The current Titanium alloy, Ti-325, will not vanish from the marketplace as a result of the proposed activity. This alloy has a firm niche as a corrosion resistant tubing material in a host of petrochemical applications, including numerous proposed coal-conversion projects. This proposed activity will open a premium market to the higher strength Ti-425 tubing material, first , as a high-value high- performance material in the high pressure hydraulic system used in Navy aircraft, and secondly, in commercial aircraft where weight reductions (in passive or semi-passive subsystems) are always needed and must be coupled to high systems reliability.
Keywords: Ti-425, Ti-425, High pressure hydraulic tubes, Pressure Impulse performance
