Effect of Processing and Composition on the Structure and Properties of P/M EP741NP Type Alloys
Author(s): John Radavich, Tadeu Carneiro, David Furrer, Joseph Lemsky, Anthony Banik
Pages: 97-106
Year: 2007 Issue: 2
Journal: CHINESE JOURNAL OF AERONAUTICS
Keyword: P/M; powder metallurgy; X-ray diffraction; EP741NP;
Abstract: A study was carried out on the effects of processing and composition on the structure and properties ofP/M EP741NP type alloys.The objectives of this study were to understand the role of Hf in a P/M superalloy containing high niobium used in aircraft engines and to determine the effects of extrusion and forging the powders as contrasted to HIPing (hot isostatic pressing) only. Two alloys of the P/M EP741NP composition were atomized: one alloy contained 0.26%Hf and the other was Hf free. After the as-atomized powders from both alloys were characterized, the powders were extruded into billets, forged and heat treated. After each process, the microstructures were characterized by SEM and the phases were extracted and identified by X-ray diffraction. The presence of Hf in the residues was probedby EDS (energy dispersive spectroscopy). The alloys were given the published Russian heat treatment as well as a more conventionalheat treatment more typical of western powder alloys. Tensile, creep and stress rupture mechanical property tests were run. Results of the structural behavior of the alloys after each processing step will be presented and discussed. The role of the Hf on the mechanical properties will be discussed.
Pages: 97-106
Year: 2007 Issue: 2
Journal: CHINESE JOURNAL OF AERONAUTICS
Keyword: P/M; powder metallurgy; X-ray diffraction; EP741NP;
Abstract: A study was carried out on the effects of processing and composition on the structure and properties ofP/M EP741NP type alloys.The objectives of this study were to understand the role of Hf in a P/M superalloy containing high niobium used in aircraft engines and to determine the effects of extrusion and forging the powders as contrasted to HIPing (hot isostatic pressing) only. Two alloys of the P/M EP741NP composition were atomized: one alloy contained 0.26%Hf and the other was Hf free. After the as-atomized powders from both alloys were characterized, the powders were extruded into billets, forged and heat treated. After each process, the microstructures were characterized by SEM and the phases were extracted and identified by X-ray diffraction. The presence of Hf in the residues was probedby EDS (energy dispersive spectroscopy). The alloys were given the published Russian heat treatment as well as a more conventionalheat treatment more typical of western powder alloys. Tensile, creep and stress rupture mechanical property tests were run. Results of the structural behavior of the alloys after each processing step will be presented and discussed. The role of the Hf on the mechanical properties will be discussed.
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