1997 TMS Annual Meeting: Tuesday Abstracts

SHAPING AND FORMING OF HIGH PERFORMANCE POWDER PRODUCTS: Session III

Session Chairperson: Prof. Henry R. Piehler, Dept. of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213

2:00 pm

MECHANICAL PROPERTIES OF LASER FORMED P/M INCONNEL AND STAINLESS STEEL: J.W. Sears, Lockheed Martin KALP, Inc., Schenectady, NY

Abstract not available.

2:30 pm

POWDER INJECTION MOLDING (PIM) OF INCONEL 718 AEROSPACE COMPONENTS: Robert M. Schmees*, Joe Spirko**, Juan Valencia**, *Pratt & Whitney, West Palm Beach, FL; **Concurrent Technologies Corp., Johnstown, PA

The feasibility and cost benefit of using PIM for the manufacture of aerospace components was investigated. An optimized thermal processing cycle was developed for hydrogen sintering, vacuum sintering, and HIPing the PIM Inconel 718 parts. The parts were subsequently solution and precipitation heat treatment. A tensile, creep, stress rupture, low cycle fatigue, and high cycle fatigue data base was generated. Tensile properties exceeded AMS 5663 minimum specification requirements. The associated cost reduction was greater than 50%. Both J52-P-409 Bushings and F119 Aircraft Mounted Nozzle Sidewall Saddle Supports were fabricated out of PIM Inconel 718.

3:00 pm

ADVANCES IN CUBIC PHASE (Al2Cr)3Ti ALLOY COATING TECHNOLOGY: D.K. Dewald*, D.E. Mikkola**, *Waubik, Inc., Hancock, MI 49930; **Dept. of Metallurgical and Materials Engineering, Michigan Technological University, Houghton, MI 49931

Cubic phase alloys of (Al2Cr)3Ti are being developed as high temperature, oxidation resistant coatings for Ti-based materials. High quality powders of these alloys have been made by high pressure gas atomization (HPGA) and are now available from a commercial powder manufacture. The powders have been applied to Ti-6Al-4V, Ti-6242, and Ti-47Al2Cr-2Nb alloy sample pieces using low pressure plasma spray (LPPS) to form coatings 100-150µm thick. Coupons cut from the samples have been subjected to high temperature cyclic oxidation tests. The as applied and oxidation tested coatings have been analyzed for structure and integrity. The results of these tests and analysis, related advancements in coating development, and powder processing will be discussed.

3:30 pm

MICROSTRUCTURAL ANALYSIS OF MECHANICALLY ALLOYED AND POWDER METALLURGY PROCESSED W-HfC AND W-Ir-HfC PENETRATOR RODS: Christine Kennedy, L.E. Murr, S. Pappu, D. Kapoor*, Dept. of Metallurgical and Materials Engineering, The University of Texas at El Paso, El Paso, TX 79968; *Army Research Development and Engineering Center, Picatinny, NJ 07806

Tungsten heavy alloys (WHA) as well as depleted uranium (DU) alloys (U-0.75% (Ti) for example) have been the primary materials employed in large caliber, U.S. tank ammunition or kinetic energy (KE) penetrators. Since the deformation behaviors and resulting ballistic performance of these alloys are different, there has been considerable effort to develop alternative and more effective penetrator materials. This study involves the mechanical alloying (MA) and PM processing of tungsten-hafnium carbide (1, 2, and 5 weight percent) and W-HfC containing 0.1% lr as a novel approach to WHA development. Slugs of W-1HfC, W-5HfC, and W-2HfC-0.5 lr and W-5HfC-0.5 lr processed from MA powder corresponding to high-speed attritor milling times ranging from 8 to 40 h, have been examined by light metallography and transmission electron microscopy (TEM). These products are remarkably free of disclocations and average (bulk) hardness range from 700 VHN for W-1HfC to 1200 VHN for W-5HfC precursor powders milled 16 h. The corresponding W-5HfC-0.5 lr hardness was 1250 VHN, and there were some interesting metallographic differences between the W-5HfC and W-5HfC-0.5 lr. HfC particle size and size distribution measurements have also been made in the TEM, and the effects of attritor milling time on residual hardness and microstructure have been examined.

4:00 pm

IN SITU METAL MATRIX COMPOSITES UTILIZING INTERMETALLIC MATRIX COMPOSITE (IMC) REINFORCEMENT: S.L Kampe*, J.S. Marte*, L. Christodoulou**, T. Zarrah**, *Virginia Polytechnic Institute and State University, Blacksburg, VA 24061; **MATSYS, Inc., Arlington, VA 22209

A new processing methodology is described whereby metal matrices are reinforced in situ by deformation-processing of metal/IMC blends. The IMC "reinforcement" is exemplified by its high strength, attributable to high loadings of dispersed ceramic (e.g. 30-50 v%) within its intermetallic matrix. Processability of the metal/IMC composite is governed by the thermodynamic compatibility of the metal and the intermetallic, and the relative high temperature flow behavior of the metal and the IMC. The methodology will be illustrated through its application to a titanium metal matrix composite, produced by hot extrusion of prealloyed Ti-6Al-4V and IMC (Al3Ti + 40 v% TiB2) powders. Microstructures and preliminary mechanical behavior will be presented for composites produced over a range of deformation processing conditions and with varying percentages of IMC reinforcement.

4:30 pm

RHEOLOGY OF POWDER INJECTION MOULDED PARTS: Sedat Özbïlen, Gazi University, Faculty Technical Education, Metal Dept., Ankara, Turkey

The determination of the variation of pressure against time for PIN feedstocks during their stay in the mould has gained importance in PIM technology, a hot research area of recent years. The possibility of this will case the control of properties of the parts that will be produced with this technology, such that the conditions to increase the productivity of the process can be realized. In the present work, the rheology of 3I6L stainless steel powder-variable binder mixes were therefore studies. Results of this investigation will be presented.