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Indexed by:期刊论文

Date of Publication:2013-11-25

Journal:JOURNAL OF ALLOYS AND COMPOUNDS

Included Journals:SCIE、EI

Volume:578

Page Number:394-404

ISSN No.:0925-8388

Key Words:Metals and alloys; Intermetallics; Phase diagrams; Rapid-solidification; Quenching; Microstructure

Abstract:Phase formation, the microstructure and its evolution, and the mechanical properties of an Al-42.2 at.% Mg alloy solidified under high pressures were investigated. After solidification at pressures of 1 GPa and 2 GPa, the main phase is the gamma phase, richer in Al than in equilibrium condition. When the pressure is further increased to 3 GPa, the main phase is the supersaturated Al(Mg) solid solution with Mg solubility up to 41.6 at.%. Unlike in similar alloys solidified at ambient pressure, the beta phase does not appear. Calculated high-pressure phase diagrams of the Al-Mg system show that although the stability range of the beta phase is diminished with pressure, it is still thermodynamically stable at room temperature. Hence, the disappearance of the beta phase is interpreted as kinetic suppression, due to the slow diffusion rate at high pressures, which inhibits solid-solid reactions. The Al-42.2 at.% Mg alloy solidified under 3 GPa has remarkably enhanced ultimate tensile strength compared to the alloy solidified under normal atmospheric pressure. (c) 2013 Elsevier B.V. All rights reserved.