MATERIALS TRANSACTIONS
Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Creep Mechanism in Several Grades of Aluminum at Low Temperatures
Tetsuya MatsunagaEiichi Sato
Author information
JOURNALS FREE ACCESS

2013 Volume 54 Issue 12 Pages 2202-2208

Details
Abstract

Creep tests were performed at less than 0.4 Tm (Tm is the melting temperature) for 99.999, 99.57 and 99.52% aluminum with several grain sizes in the range of 50–330 µm. These Al materials show remarkable creep behavior with an apparent activation energy (Q) of 30 kJ/mol, a stress exponent of 4, and a grain-size exponent of zero, and with a larger creep rate with increasing purity. These parameters resemble those of conventional dislocation creep, which is rate-controlled by the usual diffusion processes, except for the extra-low Q value. This means that a non-diffusional process affects the steady state deformation in this temperature region. Transmission electron microscopy revealed the development of a cell structure in the steady state and dislocations without any tangles in the cell interiors. Therefore, because the rate-controlling process could not occur inside of the cells, dislocation annihilation occurred through cross slip around the cell walls. According to these creep parameters and microstructural observations, the observed creep region is suggested to be a new creep region occurring through a non-diffusional process within the existing deformation mechanism map of Al at less than 0.4 Tm.

Information related to the author
© 2013 The Japan Institute of Light Metals
Previous article Next article
feedback
Top