Record Details

Comparison of gamma-gamma Phase Coarsening Responses of Three Powder Metal Disk Superalloys
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Author and Affiliation:
Gabb, T. P.(NASA Glenn Research Center, Cleveland, OH United States);
Gayda, J.(NASA Glenn Research Center, Cleveland, OH, United States);
Johnson, D. F.(NASA Glenn Research Center, Cleveland, OH, United States);
MacKay, R. A.(NASA Glenn Research Center, Cleveland, OH, United States);
Rogers, R. B.(NASA Glenn Research Center, Cleveland, OH, United States);
Sudbrack, C. K.(NASA Glenn Research Center, Cleveland, OH, United States);
Garg, A.(Toledo Univ., Toledo, OH, United States);
Locci, I. E.(Toledo Univ., Toledo, OH, United States);
Semiatin, S. L.(Air Force Research Lab., Wright-Patterson AFB, OH, United States);
Kang, E.(Northwestern Univ., Evanston, IL, United States)
Abstract: The phase microstructures of several powder metal (PM) disk superalloys were quantitatively evaluated. Contents, chemistries, and lattice parameters of gamma and gamma strengthening phase were determined for conventionally heat treated Alloy 10, LSHR, and ME3 superalloys, after electrolytic phase extractions. Several of long term heat treatments were then performed, to allow quantification of the precipitation, content, and size distribution of gamma at a long time interval to approximate equilibrium conditions. Additional coarsening heat treatments were performed at multiple temperatures and shorter time intervals, to allow quantification of the precipitation, contents and size distributions of gamma at conditions diverging from equilibrium. Modest differences in gamma and gamma lattice parameters and their mismatch were observed among the alloys, which varied with heat treatment. Yet, gamma coarsening rates were very similar for all three alloys in the heat treatment conditions examined. Alloy 10 had higher gamma dissolution and formation temperatures than LSHR and ME3, but a lower lattice mismatch, which was slightly positive for all three alloys at room temperature. The gamma precipitates of Alloy 10 appeared to remain coherent at higher temperatures than for LSHR and ME3. Higher coarsening rates were observed for gamma precipitates residing along grain boundaries than for those within grains in all three alloys, during slow-moderate quenching from supersolvus solution heat treatments, and during aging at temperatures of 843 C and higher.
Publication Date: Feb 01, 2016
Document ID:
20160001847
(Acquired Feb 17, 2016)
Subject Category: METALS AND METALLIC MATERIALS
Report/Patent Number: NASA/TM-2016-218936, E-19184, GRC-E-DAA-TN27598
Document Type: Technical Report
Contract/Grant/Task Num: NNC13BA10B; WBS 081876.02.03.04.02.01
Financial Sponsor: NASA Glenn Research Center; Cleveland, OH United States
Organization Source: NASA Glenn Research Center; Cleveland, OH United States
Description: 44p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Distribution as joint owner in the copyright
NASA Terms: HEAT RESISTANT ALLOYS; METAL POWDER; HEAT TREATMENT; MICROSTRUCTURE; HEAT OF SOLUTION; HIGH TEMPERATURE; DISSOLVING; GRAIN BOUNDARIES; ROOM TEMPERATURE; X RAY DIFFRACTION; THERMAL ANALYSIS; SIZE DISTRIBUTION
Other Descriptors: SUPERALLOYS; METALLURGY; HIGH TEMPERATURE
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