Effects of lubrication on superplastic forming of 8090 Al-Li sheets

Journal Article · Mon Aug 01 00:00:00 EDT 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90288-7· OSTI ID:7175918

Chen, T R; Huang, J C; Liauo, J M; Hwang, Y M ^[1]

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1. National Sun Yat-Sen Univ., Kaohsiung (Taiwan, Province of China)

The utilization of superplastic forming (SPF) for aluminum alloys in the aircraft industry has been a focus of study recently. In addition to the Al-Cu, Al-Mg, and Al-Zn-Mg base superplastic alloys, the Al-Li base system has attracted considerable attention. However, given the fact that the 8090 and 2090 Al-Li alloys exhibited uniaxial superplastic elongation in excess of 1,000%, the strain rate sensitivity at their optimum strain rate range is usually around 0.5[+-]0.2, compared with [approximately]0.75 seen in the 7575 Al alloys. the lower m-value in the Al-Li alloys might suggest a less uniform strain distribution during SPF, which will be of great concern in practice and is worth further careful studies. One of the improvement methods along this line is to use appropriate lubricants. The thickness distributions have been reported to be improved by the use of lubricants. Typical lubricants used for superplastic forming are graphite, boron nitride, molybdenum disulfide, etc. The rejection force needed for removing the formed specimen from the close-die can also be reduced significantly by using lubricants. The current study is to examine the forming behavior of the 8090 Al-Li alloy superplastically formed in a circular open (free bulging) or close die to variable levels of depth, with or without lubrication.

• OSTI ID: 7175918
• Journal Information: Scripta Metallurgica et Materialia; (United States), Vol. 31:3; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
MATERIALS WORKING
LITHIUM ALLOYS
COMPUTERIZED SIMULATION
EXPERIMENTAL DATA
GRAPHITE
LUBRICANTS
MOLYBDENUM SILICIDES
PLASTICITY
ALLOYS
CARBON
DATA
ELEMENTAL MINERALS
ELEMENTS
FABRICATION
INFORMATION
MECHANICAL PROPERTIES
MINERALS
MOLYBDENUM COMPOUNDS
NONMETALS
NUMERICAL DATA
REFRACTORY METAL COMPOUNDS
SILICIDES
SILICON COMPOUNDS
SIMULATION
TRANSITION ELEMENT COMPOUNDS
360101* - Metals & Alloys- Preparation & Fabrication