SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  AF071-135 (AirForce)
Title:  Weld Repair of Titanium Alloys for Turbine Engine Applications
Research & Technical Areas:  Materials/Processes

  Objective:  Develop a process to weld repair a titanium bladed disk/rotor in a practical, cost-effective manner while meeting the minimum mechanical property requirements to ensure durability.
  Description:  Newer advanced turbine engines incorporate integrally bladed rotors or disks, commonly referred to as IBRs or blisks, in the fan and compressor regions. IBRs/blisks are used because they increase engine efficiency while reducing part count and weight. However, the IBRs/blisks have also introduced new and unique challenges for repair due to foreign object damage (FOD), domestic object damage (DOD), and wear. Traditional engine designs allow individual airfoils to be removed and repaired or replaced with a new airfoil if they are damaged beyond blendable limits. This is not an effective solution for IBRs/blisks since it would require the replacement of the entire blade/disk assembly, which is cost prohibitive. It is therefore imperative that a cost-effective solution be developed to repair IBRs/blisks that have been damaged due to FOD, DOD, and wear. The goal of this project is to develop a weld repair process (including traditional welding techniques as well as newer methods such as laser additive processes) for applicable titanium engine components that have been exposed to service conditions in a turbine engine. The repair process would be developed on material in as used condition, i.e. after undergoing thermal and/or mechanical cycling and in the final machined state. The repair process should produce defect-free welds in accordance with IAW AMS 2680 acceptance requirements and exhibit mechanical properties equal to or better than the conditioned material. Applicable titanium alloys include, but are not limited to, Ti-6246, Ti-6242, and Ti-17.

  PHASE I: Determine the technical feasibility of weld repairing titanium blisks/IBRs while meeting remaining life requirements. The demonstration should include the ability to produce crackfree welds on an applicable titanium alloy.
  
  PHASE II: Demonstrate the weld repair process on an applicable titanium alloy. Weld repair should produce crackfree welds, return material properties to near original baseline level, and meet remaining life requirements. Feasibility of developing the repair into a cost-effective, commercially viable process should also be demonstrated.

  DUAL USE COMMERCIALIZATION: Military application: The repair process developed under this program will have applicability to all military turbine engines. Commercial application: The repair process developed under this program will have applicability to both military and commercial aircraft, as well as land-based turbine engines.

  References:  1. Younossi, O. et al., “Military Jet Engine Acquisition: Technology Basis and Cost-Estimating Methodology,” Rand Corporation, Chapter 3, http://www.rand.org/pubs/monograph_reports/2005/MR1596.pdf

Keywords:  IBR, blisk, bladed disk, repair, weld, titanium

Questions and Answers:
Q: 1. Is the author looking for a manual or automated process for these repairs?
2. What is the overall dimension of the full assembly?
3. Is filler material in wire form preferred over powder?
A: 1. The process can be manual or automated. However, process control and repeatability will be important.
2. This process will be targeted towards repair of turbine engines for military fighter aircraft. The exact dimensions will vary based on the specific engine and stage.
3. There is no preferred filler material.
Q: 1. Is the author looking for a manual or automated process for these repairs?
2. What is the overall dimension of the full assembly?
3. Is filler material in wire form preferred over powder?
A: 1. The process can be manual or automated. However, process control and repeatability will be important.
2. This process will be targeted towards repair of turbine engines for military fighter aircraft. The exact dimensions will vary based on the specific engine and stage.
3. There is no preferred filler material.

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