Journal Published Online: 28 May 2019
Volume 8, Issue 5

On the Phases Present in Artificially Aged AA2618 Extrusions

CODEN: MPCACD

Abstract

The aluminum alloy AA2618, based on aluminum–copper–magnesium–silicon–iron–nickel, is successfully utilized at elevated temperatures, i.e., in the temperature range of 100°C–300°C, for varying durations for critical aerospace applications. The intermetallic compound Al9FeNi (having the monoclinic crystal structure) forms early during the solidification process, and this compound is known to assist in stabilizing the grain structure of the alloy. This work shows that during subsequent homogenizing, annealing, and thermo-mechanical processing, the Al9FeNi compound becomes unstable and acts as a nucleation site for the stable Al7Cu2(FeNi) phase (having a tetragonal crystal structure). It is further observed that in the artificially aged condition, both Guinier–Preston–Bagaryatsky zones and S (Al2CuMg) phase co-exist. However, the S phase is found to form copiously parallel to {110}Al crystallographic planes apart from its known habit planes of {210}Al.

Author Information

Mukhopadhyay, A. K.
Defence Metallurgical Research Laboratory, Defence Research and Development Organization, Kanchanbagh, Hyderabad, India
Sarkar, R.
Defence Metallurgical Research Laboratory, Defence Research and Development Organization, Kanchanbagh, Hyderabad, India
Kumar, D.
Defence Metallurgical Research Laboratory, Defence Research and Development Organization, Kanchanbagh, Hyderabad, India
Ghosal, P.
Defence Metallurgical Research Laboratory, Defence Research and Development Organization, Kanchanbagh, Hyderabad, India
Pages: 11
Price: $25.00
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Details
Stock #: MPC20180172
ISSN: 2379-1365
DOI: 10.1520/MPC20180172