The University of Southampton
University of Southampton Institutional Repository

Cooling and heating rate dependence of precipitation in an Al-Cu alloy

Cooling and heating rate dependence of precipitation in an Al-Cu alloy
Cooling and heating rate dependence of precipitation in an Al-Cu alloy
Differential scanning calorimetry and X-ray diffraction were used to study the cooling and heating rate dependence of precipitation in an Al-1.66 at.% Cu alloy. After homogenizing, cooling at a rate of 22 K min?1 (SC22) is sufficient to retain all copper in solid solution. GP-zone formation during subsequent heat treatment is hindered; this is ascribed to an insufficient number of (excess) vacancies. After a water quench (WQ) a large number of GP zones are formed during subsequent storage at room temperature for 1 h. The heat content of the GP-zone dissolution effect can quantitatively be described in terms of the heat of precipitation of GP I zones and the solid solubilities as derived from the GP I zone solvus. The heat content of the combined ??-/?-phase precipitation effect appeared to be proportional to the number of copper atoms precipitated, yielding an average value for the heat of copper precipitation of 36 kJ mol?1 copper. The activation energy for ??-phase formation is 0.75 eV for SC22 specimens and 1.10 ± 0.10 eV for WQ specimens. The differences in reported activation energies for ??-phase formation are discussed in terms of mobility of dissolve atoms (related to the vacancy concentration), interfacial energy and direction of growth (normal or perpendicular to the ??-phase plate).
0921-5093
183-194
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
van Mourik, P.
47b86384-abdc-4cef-9e8f-a9d5bd86f12d
Starink, M.J.
fe61a323-4e0c-49c7-91f0-4450e1ec1e51
van Mourik, P.
47b86384-abdc-4cef-9e8f-a9d5bd86f12d

Starink, M.J. and van Mourik, P. (1992) Cooling and heating rate dependence of precipitation in an Al-Cu alloy. Materials Science and Engineering: A, 156 (2), 183-194. (doi:10.1016/0921-5093(92)90150-Y).

Record type: Article

Abstract

Differential scanning calorimetry and X-ray diffraction were used to study the cooling and heating rate dependence of precipitation in an Al-1.66 at.% Cu alloy. After homogenizing, cooling at a rate of 22 K min?1 (SC22) is sufficient to retain all copper in solid solution. GP-zone formation during subsequent heat treatment is hindered; this is ascribed to an insufficient number of (excess) vacancies. After a water quench (WQ) a large number of GP zones are formed during subsequent storage at room temperature for 1 h. The heat content of the GP-zone dissolution effect can quantitatively be described in terms of the heat of precipitation of GP I zones and the solid solubilities as derived from the GP I zone solvus. The heat content of the combined ??-/?-phase precipitation effect appeared to be proportional to the number of copper atoms precipitated, yielding an average value for the heat of copper precipitation of 36 kJ mol?1 copper. The activation energy for ??-phase formation is 0.75 eV for SC22 specimens and 1.10 ± 0.10 eV for WQ specimens. The differences in reported activation energies for ??-phase formation are discussed in terms of mobility of dissolve atoms (related to the vacancy concentration), interfacial energy and direction of growth (normal or perpendicular to the ??-phase plate).

Text
Starink & van Mourik 1992 MSEA.pdf - Version of Record
Restricted to Repository staff only
Request a copy

More information

Published date: 15 August 1992
Organisations: Engineering Mats & Surface Engineerg Gp

Identifiers

Local EPrints ID: 375705
URI: http://eprints.soton.ac.uk/id/eprint/375705
ISSN: 0921-5093
PURE UUID: 0baff1d1-db8d-4414-957a-64b9abbe7c7c

Catalogue record

Date deposited: 13 Apr 2015 09:17
Last modified: 14 Mar 2024 19:30

Export record

Altmetrics

Contributors

Author: M.J. Starink
Author: P. van Mourik

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×