Hot deformation behavior of 7150 aluminum alloy during compression at elevated temperature

Journal Article · Mon Jun 15 04:00:00 EDT 2009 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2008.12.012· OSTI ID:22066099

Nengping, Jin ^[1]; Yi, Han; Wenxiang, Wu ^[2]; Jianghua, Chen ^[1]

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1. College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)
2. Suzhou Institute for Nonferrous Metal Processing Technology, Suzhou 215026 (China)

Hot compression tests of 7150 aluminum alloy were preformed on Gleeble-1500 system in the temperature range from 300 deg. C to 450 deg. C and at strain rate range from 0.01 s{sup -1} to 10 s{sup -1}, and the associated structural changes were studied by observations of metallographic and transmission electron microscope. The results show that the true stress-true strain curves exhibit a peak stress at a critical strain, after which the flow stresses decrease monotonically until high strains, showing a dynamic flow softening. The peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by a Zener-Hollomon parameter in the hyperbolic-sine equation with the hot deformation activation energy of 229.75 kJ/mol. In the deformed structures appear the elongated grains with serrations developed in the grain boundaries, decreasing of Z value leads to more adequate proceeding of dynamic recrystallization and coarser recrystallized grains. The subgrains exhibit high-angle sub-boundaries with a certain amount of dislocations and large numbers of dynamic precipitates in subgrain interiors as increasing Z value. The dynamic recovery and recrystallization are the main reasons for the flow softening at low Z value, but the dynamic precipitates and successive dynamic particles coarsening have been assumed to be responsible for the flow softening at high Z value.

• OSTI ID: 22066099
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: 6 Vol. 60; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
COMPRESSION
DEFORMATION
DISLOCATIONS
FLOW STRESS
GRAIN BOUNDARIES
MATERIALS TESTING
METALLOGRAPHY
PARTICLES
PRECIPITATION
RECRYSTALLIZATION
STRAIN RATE
STRAINS
TEMPERATURE DEPENDENCE
TRANSMISSION ELECTRON MICROSCOPY