Effect of two-stage strain-rate test on the superplastic behavior of an Al-Li-Cu-Mg-Zr alloy; Mechanical behavior

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Scripta Metallurgica; (United States)

DOI:https://doi.org/10.1016/0956-716X(91)90363-6· OSTI ID:5126326

Liu, Q ^[1]; Yang, J; Yao, M ^[2]

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1. Analysis and Measurement Centre, Harbin Inst. of Tech., Harbin 150006 (CN)
2. Dept. of Metals and Technology, Harbin Inst. of Tech., Harbin 150006 (CN)

Fine grain size is one of the essential conditions for obtaining superplasticity in polycrystalline materials. Several methods are available for grain refinement, including phase transformation, recrystallization, working of duplex alloys, and phase separation in duplex alloys. Recrystallization has been extensively used for grain refinement of superplastic quasi-single phase aluminum-base alloys. There are two kinds of superplastic Al-base alloys. In one of them, a fine grain size microstructure is obtained by static recrystallization microstructure is obtained by deformation-induced recrystallization during the initial stage of superplastic deformation. In the case of Al-Li base alloys, either method can be adopted for obtaining superplasticity. However, the deformation-induced recrystallization method can make the alloy more superplastic at higher strain-rates, which is more attractive for industrial applications. The paper examines the effect of two stage strain rate tests on stress-strain curves and superplasticity of an Al-Li-Cu-Mg-Zr alloy in detail. The results show that the proper combination of deformation parameters in a two-stage strain rate test results in higher elongation than that in a single strain-rate test. The optimum deformation condition corresponds to the proper combination of strain rate hardening and strain hardening in the second stage of superplastic deformation, which keeps the engineering stress constant or slightly increasing and provides a high necking resistance.

• OSTI ID: 5126326
• Journal Information: Scripta Metallurgica; (United States), Journal Name: Scripta Metallurgica; (United States) Vol. 25:1; ISSN 0036-9748; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM BASE ALLOYS
CRYSTAL STRUCTURE
DEFORMATION
FLOW STRESS
GRAIN SIZE
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
LATTICE PARAMETERS
LITHIUM ALLOYS
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
OPTIMIZATION
PLASTICITY
RECRYSTALLIZATION
SIZE
STRESSES