ELECTRON BEAM PROCESSING

THE USE OF HIGH ENERGY (E ~ 1-5 MEV) ELECTRON BEAMS (HEEB) AT HIGH AVERAGE POWER (P ~ 200 KILL - I MW) ALLOWS THE COST EFFECTIVE PROCESSING AND FABRICATION OF UNIQUE GRADED COMPOSITION MATERIALS WHICH ARE NOT ECONOMICALLY VIABLE USING CONVENTIONAL FABRICATION METHODS. EXAMPLES OF SUCH MATERIALS ARE SUPERALLOYS AND METAL-MATRIX COMPOSITES WITH GRADED THERMAL AND MECHANICAL PROPERTIES. A GRADED COMPOSITION NICKEL-BASED SUPERALLOY AIRCRAFT TURBINE DISK FABRICATED USING HEEB POWDER METALLURGY TECHNIQUES WOULD OPERATE AT HIGHER TEMPERATURES WITH THE IMPROVED DEFORMATION RESISTANCE NEEDED FOR THE HIGH SPEED CIVILIAN TRANSPORT AND NEXT GENERATION FIGHTER AIRCRAFT. A HEEB MATERIAL PROCESSING SYSTEM WOULD ALSO ALLOW COST EFFECTIVE SURFACE HARDENING OF STEEL UP TO DEPTHS OF 5 MM. THE AVERAGE POWER LEVELS NOW AVAILABLE USING HEEB ARE 5-25 TIMES HIGHER THAN COMPETING PROCESSING TECHNOLOGIES SUCH AS LASER LAYER GLAZING AND PLASMA SPRAYING. HIGH AVERAGE POWER CONTRIBUTES TO HIGH THROUGHPUT AND COST EFFECTIVE HEEB MATERIAL PROCESSING SYSTEMS. SCIENCE RESEARCH LABORATORY (SRL) HAS DEVELOPED A NEW GENERATION OF PULSED INDUCTION LINEAR ACCELERATORS WHICH ALLOW RELIABLE, COST EFFICIENT PRODUCTION OF HIGH AVERAGE POWER ELECTRON BEAMS WITH THE NECESSARY PARAMETERS FOR HEEB MATERIAL PROCESSING. A UNIQUE FEATURE OF THESE ACCELERATORS IS THE HIGH REPETITION RATE (>5000 PPS) ALL-SOLID-STATE PULSED POWER DRIVERS WHICH MAKE THESE ACCELERATORS SCALABLE TO MW POWER LEVELS AT AN ELECTRON BEAM COST OF LESS THAN $1/WATT. A HEEB MATERIAL PROCESSING SYSTEM BASED ON THIS TECHNOLOGY IS DESCRIBED. EXPERIMENTS TO BE CONDUCTED IN PHASE II WILL DEMONSTRATE COST EFFECTIVE HEEB PROCESSING SYSTEMS FOR FABRICATION OF GRADED ALLOY TURBINE DISKS AND SURFACE HEAT TREATMENT OF RAIL STEELS. ANTICIPATED BENEFITS/POTENTIAL APPLICATIONS - INDUCTION ACCELERATOR BASED HEEB MATERIAL PROCESSING SYSTEMS HAVE THE POTENTIAL TO PRODUCE NEW MATERIALS OF MILITARY INTEREST. TWO APPLICATIONS DESCRIBED IN THIS PROPOSAL ARE GRADED SUPERALLOY AIRCRAFT TURBINE DISKS AND RAIL STEELS SURFACE HARDENED TO DEPTHS OF UP TO 5 MM.