Design and development of hot corrosion-resistant nickel-base single-crystal superalloys by the d-electrons alloy design theory: Part II--Effect of refractory metals Ti, Ta, and Nb on microstructures and properties

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02646524· OSTI ID:5729746

Zhang, J S ^[1]; Hu, Z Q ^[2]; Murata, Y; Morinaga, M; Yukawa, N ^[3]

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1. Academia Sinica, Shenyang (China). Inst. of Metal Research Beijing Univ. of Science and Technology, (China)
2. Academia Sinica, Shenyang (China). Inst. of Metal Research
3. Toyohashi Univ. of Technology (Japan). Dept. of Production Systems Engineering

A systematic study of the effects of refractory metals Ti, Ta, and Nb on the microstructures and properties was conducted with a hot corrosion-resistant alloy system Ni-16Cr-9Al-4Co-2W-1Mo-(0 [approximately] 4)Ti-(0 [approximately] 4)Ta-(0 [approximately] 4)Nb (in atomic percent) which was selected based on the d-electrons alloy design theory and some basic considerations in alloying features of single-crystal nickel-base superalloys. The contour lines of solidification reaction temperatures and eutectic ([gamma] + [gamma][prime]) volume fraction in the Ti-Ta-Nb compositional triangle were determined by differential thermal analysis (DTA) and imaging analyzer. Compared with the reference alloy IN738LC, in most of the compositional ranges studied, the designed alloys show very low amounts of eutectic ([gamma] + [gamma][prime]) ([le]0.4 vol pct), narrow solidification ranges ([le]65 C), and wide heat-treatment windows'' (> 100 C). This indicates that the alloys should have the promising microstructural stability, single-crystal castability, and be easier for complete solution treatment. In a wide compositional range, the designed alloys showed good hot corrosion resistance (weight loss less than 20 mg/cm[sup 2] after 24 hours kept in molten salt at 900 C). By summarizing the results, the promising alloy compositional ranges of the alloys with balanced properties were determined for the final step of the alloy design, i.e., to grow single crystal and characterize mechanical properties of the alloys selected from the previously mentioned regions.

• OSTI ID: 5729746
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 24:11; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
360105 -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
ALUMINIUM ALLOYS
CHROMIUM ALLOYS
COBALT ALLOYS
COMPARATIVE EVALUATIONS
CORROSION RESISTANCE
DESIGN
EVALUATION
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INCONEL 738
INCONEL ALLOYS
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
NIOBIUM ALLOYS
PHASE TRANSFORMATIONS
SOLIDIFICATION
TANTALUM ALLOYS
TITANIUM ALLOYS
TUNGSTEN ALLOYS