Development of Improved Metal-Matrix Fabrication Techniques for Aircraft Structures

摘要

Material evaluation was performed on several composites including plasma-sprayed and diffusion-bonded boron or Borsic/6061 Al tape forms, composites with transverse reinforcements (Ti and stainless steel), and Borsic/713 Al plasma-sprayed tape. It was demonstrated that complicated structural shapes such as tapered frames and hat sections could be successfully fabricated by tape consolidation methods. A new fabrication process, Con Braz joining, was developed that promises significant cost reductions for future composite hardware. A CURVED UNIDIRECTIONAL I-beam was creep- formed to a 60-inch radius, demonstrating the adaptability of forming composites to non-planer shapes. Significant cost reductions in machining were accomplished through the utilization of a rotary ultrasonic machine. Resistance spot welding and spot joining schedules were developed, several brazing methods were investigated and data was generated on properties of mechanically fastened composites, both with and without the aid of adhesives. Several structural elements, were designed, fabricated, and tested. SStructures fabricated by the Con Braz joining method had superior load carrying abilities when compared to those made by conventional tape consolidation (both high-and low-pressure autoclave bonding). From work performed on this program it is concluded that metal- matrix aircraft structures can be fabricated at reasonable costs using conventional metal working methods. (Author-PL)