AN ALUMINUM RIVET FOR USE ABOVE 500 DEG F DEVELOPMENT

THE AL-FE-X FAMILY OF ALUMINUM IS PROPOSED FOR USE ON THE AIRFRAME OF THE ADVANCED TACTICAL FIGHTER (ATF). THE NEW ALLOY MAINTAINS ITS STRUCTURAL PROPERTIES ABOVE 500 DEG F, THE TEMPERATURE REQUIRED OF AN AIRFRAME CAPABLE OF EXTENDED OPERATION AT MACH 3. A NEW HIGH TEMPERATURE FASTENER MUST BE DEVELOPED TO FULLY REALIZE THIS ALLOY'S PROPERTIES. MEASUREMENT TECHNOLOGY NORTHWEST (MTNW) SUGGESTS THAT THE MOST ATTRACTIVE ALTERNATIVE WILL BE A SLUG RIVET OF THE SAME AL-FE-X MATERIAL. A SLUG RIVET IS LOW IN COST AND PROVIDES BETTER FATIGUE CHARACTERISTICS THAN A PREHEADED RIVET. SEVERAL INSTALLATION TECHNIQUES WILL BE TESTED. MTNW PROPOSES TO MACHINE BOTH SLUG AND COUNTERSUNK RIVETS FROM BILLET MATERIAL OF AL-FE-CE AVAILABLE THROUGH AN AGREEMENT WITH ALCOA. UPSET PARAMETERS WILL BE MONITORED. TEST METHODS FOR JOINT YIELD AND ULTIMATE STRENGTH AT ROOM AND ELEVATED TEMPERATURE WILL BE CONDUCTED. MICROSTRUCTURAL ANALYSIS WILL ALSO BE EMPLOYED. THE IMPORTANCE OF THE FASTENER INSTALLATION TECHNIQUE AS WELL AS THE FASTENER INTERFERENCE PATTERN WILL BE INVESTIGATED. FATIGUE TEST COUPONS WILL BE SUPPLIED TO THE AIR FORCE.