Quasicrystalline phase-reinforced Mg-based metallic alloy with high warm and hot formability and method of making the same

Abstract

Disclosed is a quasicrystalline phase-reinforced Mg-based metallic alloy with high warm and hot formability, and making method thereof. The metallic alloy comprises a composition of Mg-1~10 at % Zn-0.1~3 at % Y, in which a two-phase region consisting of a quasicrystalline phase and a magnesium-based solid solution phase exists. Constituting a matrix structure, the Mg-based solid solution phase (alpha-Mg) is formed as a primary solid phase upon solidification. The quasicrystalline phase serves as a second phase and forms, together with the Mg-based solid solution phase, a eutectic phase, thereby reinforcing the matrix. The materials obtained through the hot rolling or extrusion of the cast alloy have an increased volume % of the second phase and thus show significantly increased strength.

Description

[0001] 1. Field of the Invention[0002] The present invention relates, in general, to a quasicrystalline phase-reinforced Mg-based metallic alloy superior in warm and hot formability and, more particularly, to an Mg--Zn--Y alloy which has a two-phase region consisting of a quasicrystalline phase and a magnesium-based solid solution phase, in which the solid solution is formed as a primary phase constituting a matrix structure upon solidification, while the quasicrystalline phase serves as a second phase and forms, together with the solid solution phase, a eutectic phase, thereby reinforcing the matrix.[0003] 2. Description of the Prior Art[0004] Casings for portable electronic appliances, such as mobile phones, or materials for automobile parts are required to be of light weight, high strength, high toughness, and high formability.[0005] While crystals generally have one-, two-, three-, and six-fold rotational axes of symmetry only, quasicrystals have five-, eight-, ten-and twelve-fo...

AI Technical Summary

Benefits of technology

The alloy exhibits improved warm and hot formability, increased strength, and elongation, with a stable interface between the quasicrystalline phase and matrix, enabling the production of high-quality, lightweight materials suitable for various applications.

Problems solved by technology

Superior as they are in hardness as compared to crystals of similar compositions, quasicrystals are unsuitable for use as sole structural materials owing to their high brittleness.

The composite materials of the cited reference have the advantage of being made to show versatile mechanical properties by controlling the amounts of components, but the disadvantage of being poor in bonding strength between component particles.

In case particles that are likely to be coated with oxides, such as aluminum or aluminum alloy particles, are used as starting materials, the oxide coatings deteriorate the bonding between the matrix metal particles and the reinforcement particles, giving rise to a decrease in mechanical properties, especially elongation and fracture toughness.

Additionally, the composite materials are not advantageous in terms of product reliability and production cost owing to their complicated production procedure and many production parameters.

Further, Al--Cu--Fe alloy is unsuitable as materials for use in casings for electronic appliances or materials for automobile parts, which require lightness, high strength, high toughness and high formability because the quasicrystalline phase region in Al--Cu--Fe alloy is surrounded by various brittle intermetallic phase regions.

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