SEDL / STP / STP1165-EB / STP25113S

Microstructural Investigations of Rapidly Solidified Copper-Niobium (Cu-Nb) Alloy Powders Produced by Inert Gas Atomization

Zeik, KL
Senior research engineer, Unit of USX Corporation, Monroeville, PA

Anderson, IE
Staff metallurgist, Ames Laboratory, The Iowa State University, Ames, IA

Koss, DA
Professor of Metallurgy and department chair, The Pennsylvania State University, University Park, PA

Howell, PR
Professor of Metallurgy, The Pennsylvania State University, University Park, PA

Pages: 9    Published: Jan 1993

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Abstract

This study presents a metallographic technique that enables the microstructural examination of the cross-sections of individual, fine-scale (10 to 75 μm) powder particles. The technique was developed to permit characterization of the “as-solidified” features of copperbased powders produced by high-pressure inert gas atomization (HPGA) in order to relate the microstructures to processing history. In order to perform the necessary microscopy to elucidate the microstuctural features, a metallographic technique was developed to permit characterization of the “as-atomized” microstructures within the individual powder particles. This technique involved classifying, mounting, and polishing through the diameters of individual powder particles and then using an “attack etch” to remove some of the copper matrix. This enabled characterization of the niobium-rich second phase. Secondary electron imaging on a scanning electron microscope provided the necessary resolution to characterize the second phase morphologies as a function of powder-particle size, ultimately relating the microstructures to processing conditions.