Powder Metallurgical Innovations for Improved Hot-Section Alloys in Aeroengine Applications

Abstract

Throughout the past decade a number of new powder metallurgy processes have appeared which offer con siderable promise for superior aeroengine combustor, blade, and disc alloys. Furthermore, several features of these processes can be exploited for improved material utilization such that total manufacturing costs are contained to combat steep increases in basic alloying element prices. The processes include gas atomization of superalloy powder for critical rotating parts, rotating electrode atomization for titanium powder in similar components, controlled thermomechanical processing of attrited powders to produce oxide dispersion strengthened superalloy sheet and airfoil parts, and finally plasma-sprayed gas-atomized powder for advanced hot-section overlay and thermal barrier coatings. Considerable alloy and process development work has already been undertaken on all these systems by aeroengine material suppliers and advantages accruing in terms of superior properties and/or lower processing costs demonstrated at laboratory level and for some cases also in engine service. PM/0186

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