Low quench sensitivity of superplastic 8090 Al-Li thin sheets

Journal Article · Tue Oct 01 00:00:00 EDT 1996 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/BF02663842· OSTI ID:417851

Chen, T R; Peng, G J; Huang, J C ^[1]

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1. National Sun Yat-Sen Univ., Kaohsiung (Taiwan, Province of China). Inst. of Materials Science and Engineering

Quench sensitivity of the superplastic 8090 Al-Li thin sheets was investigated from the strengthening point of view for the various precipitates formed in the alloy. Specimens subjected to different cooling rates (water quenching, silicon oil cooling, and air cooling) from solution treatment (or superplastic forming) temperature were examined by tensile tests, transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Experimental results show that {delta}{prime} is the predominant phase in the alloy under all cooling conditions. Because {delta}{prime} could be formed in a similar amount and size after the T6 treatment, and because the amount of S{prime} precipitates and T{sub 2} particles were extremely low, the superplastic 8090 Al-Li alloy would, thus, always exhibit low quench sensitivity. Based on DSC and high resolution electron microscopy (HREM) studies, new interpretations of the first two exotherms of the DSC traces were made. Strong evidence shows that the first exothermic peak is attributed to the further precipitation of {delta}{prime} phase, and the second one is contributed from the Al-Cu-Mg GPB zone formation.

• Sponsoring Organization: USDOE
• OSTI ID: 417851
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 10 Vol. 27; ISSN 1073-5623; ISSN MMTAEB
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
AIRCRAFT COMPONENTS
ALUMINIUM BASE ALLOYS
CALORIMETRY
CHEMICAL COMPOSITION
COPPER ALLOYS
HEAT TREATMENTS
LITHIUM ALLOYS
MAGNESIUM ADDITIONS
MATERIALS
MICROHARDNESS
MICROSTRUCTURE
PRECIPITATION
QUENCHING
SAMPLE PREPARATION
TENSILE PROPERTIES
TRANSMISSION ELECTRON MICROSCOPY
ZIRCONIUM ADDITIONS