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Development of a submicrometer-grained microstructure in aluminum 6061 using equal channel angular extrusion

Published online by Cambridge University Press:  31 January 2011

Stephane Ferrasse
Affiliation:
Mechanical Engineering Department, Texas A&M University, College Station, Texas 77843-3123
Vladimir M. Segal
Affiliation:
Mechanical Engineering Department, Texas A&M University, College Station, Texas 77843-3123
K. Theodore Hartwig
Affiliation:
Mechanical Engineering Department, Texas A&M University, College Station, Texas 77843-3123
Ramon E. Goforth
Affiliation:
Mechanical Engineering Department, Texas A&M University, College Station, Texas 77843-3123
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Abstract

Submicrometer-grained (SMG) microstructures are produced in an Al–Mg–Si alloy (6061) by subjecting peak-aged and overaged billets of the alloy to intense plastic strain by a process known as equal channel angular extrusion. Two types of refined structure are distinguished by optical and transmission electron microscopy. One structure is created through intense deformation (four extrusion passes through a 90° die, ε = 4.62) by dynamic rotational recrystallization and is a well-formed grain (fragmented) structure with a mean fragment or grain size of 0.2–0.4 μm. The other structure is produced by post-extrusion annealing through static migration recrystallization, resulting in a grain size of 5–15 μm. Intense deformation of peak-aged material to a true strain ε of 4.62 (four passes) produces a strong, ductile, uniform, fine, and high angle grain boundary microstructure with increased stability against static recrystallization as compared to the overaged material.

Type
Articles
Copyright
Copyright © Materials Research Society 1997

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