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기술보고서

기술보고서 게시판 내용
타이틀	Tensile Properties of GRCop-84
저자	Ellis, David L.;; Loewenthal, William S.;; Yun, Hee-Man
Keyword	ANNEALING;; COPPER ALLOYS;; CREEP STRENGTH;; CYCLES;; HEAT TREATMENT;; HIGH TEMPERATURE;; HOT ISOSTATIC PRESSING;; PRECIPITATES;; REUSABLE LAUNCH VEHICLES;; STABILITY;; TENSILE PROPERTIES
URL	http://hdl.handle.net/2060/20120008551
보고서번호	NASA/TM-2012-217108
발행년도	2012
출처	NTRS (NASA Technical Report Server)
ABSTRACT	This is a chapter in the final report on GRCop-84 for the Reusable Launch Vehicle (RLV) Second Generation/Project Constellation Program. It contains information on the tensile properties of GRCop-84. GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) was produced by extrusion and Hot Isostatic Pressing (HIPing). Some of the extrusions were rolled to plate and sheet while other extrusions were drawn into tubing. The material was further subjected to various heat treatments corresponding to annealing, anticipated typical brazing conditions, an end-of-life condition and various elevated temperature exposures to attempt to improve creep resistance. As anticipated, cold work increased strength while decreasing ductility. Annealing at 600 C 񡻘 F) and higher temperatures was effective. An exposure for 100 h at 500 C 鿤 F) resulted in an increase in strength rather than the anticipated decrease. High temperature simulated-braze cycles and thermal exposures lowered the strength of GRCop-84, but the deceases were small compared to precipitation strengthened copper alloys. It was observed that the excess Cr could form large precipitates that lower the reduction in area though it appears a minimum amount is required. Overall, GRCop-84 exhibits good stability of its tensile properties, which makes it an excellent candidate for rocket engine liners and many other high temperature applications.