S. M. El-Soudani, The Boeing Company, Huntington Beach, CA; O. Yu, RMI Titanium Company, Niles, OH; F. Sun, RTI International Metals Inc., Niles, OH; A. Keskar, RTI International Metals, Inc.,, Houston, TX; V. S. Moxson, V. Duz, ADMA Products, Twinsburg, OH
Using the results of a workability study program in combination with prior extrusion experience at RTI, the feasibility of canless extrusion in ambient environment of hydride/dehydride blended elemental, Ti-6AL-4V ADMA-Processed powder, previously direct-consolidated by cold isostatic pressing (CIP), followed by vacuum sintering has been successfully demonstrated. The workability tests of powder-based elevated temperature compression specimens showed that powder-based consolidated billets of similar baseline composition as for wrought ingot-based Ti-6AL-4V billets will require lower extrusion pressures at same extrusion temperatures and strain rates. Laboratory analysis showed that the canless powder-based billet extrusion processing step conducted in air added no more than 200 ppm oxygen to the as-vacuum-sintered billet oxygen content. Preliminary tensile properties of the blended-elemental ADMA powder-based extrusions of a Ti-6AL-4V composition processed both in the beta or alpha-beta ranges of extrusion temperatures showed at least equivalent tensile properties as compared to identically processed wrought, ingot-based and extruded Ti-6AL-4V billet materials. In the blended elemental powder-based extrusions both nitrogen and carbon contents were within specification limits for Ti-6AL-4V alloy, while any excessive residual hydrogen was successfully vacuum degassed after extrusion to within specification limits. Further optimization for fracture toughness, stress-corrosion resistance and fatigue properties will build on these encouraging results, while monitoring and controlling powder-based product interstitial content, namely oxygen uptake during pre-extrusion powder-consolidation processing steps.
Summary: to be submitted later
