F-35 Direct Manufacturing: Material Qualification Results

The F-35 Program is actively pursuing qualification of Direct Manufactured (DM) titanium alloy structural hardware.  The F-35 DM process is an additive manufacturing procedure using an electron beam (EB) vacuum chamber, feedstock weld wire, and closed-loop process controls to ensure a consistent product.  Lockheed Martin has generated material specifications to define the DM material characteristics and is currently engaged in the material qualification program that is scheduled for completion first quarter 2012.

The primary advantages of the F-35 EBDM process are affordability benefits derived from a reduction in raw materials and machining expenses as well as a significant reduction in lead times from a concept design to prototype hardware to production parts.  The F-35 EBDM process for fabricating large structural hardware is proving its viability over other additive manufacturing techniques due to its large deposition rates (greater than 5 lbs/hr and increasing) and its customizable sized chambers (currently up to 20’ x 7’ x 5’ and several hundred pounds). 

A necessity before embarking on a material qualification test program is to define a fabrication process that can and will produce a consistent product.  This has been accomplished with the selection of a closed loop process control system jointly developed with Sciaky, Inc.  The system has been optimized for the repeatable deposition of large titanium pre-forms using F-35 specifications. 

The objective of this presentation will be to report the results of the materials qualification test program.  This test program consists of ten (10) large pre-forms (approximately 250 lbs – 300 lbs of deposited titanium) that were sectioned to more than 1700 coupon test specimens.  Testing includes static and fatigue evaluations and the results will be directly compared to existing F-35 Program design properties.