AMORPHOUS METALS
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Written by tom
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Monday, 21 April 2008 |
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AMORPHOUS METALS. Also known as metallic glasses and glassy metals, they have a noncrystalline structure that is achieved by quenching of metal-metalloid alloys.
Unlike normal metals, amorphous metals have no grains or grain boundaries, thus resulting in a tight atomic network. In general they are more corrosion-resistant than crystalline metals, and they have high mechanical strength and hardness. Perhaps of greatest impor-
tance are their magnetic properties. The absence of grain boundaries allows magnetic domains to move freely as magneticiield is changed. This results in very low hysteresis and power losses, thus making these materials attractive for transformer cores. Although glasslike, amorphous metals are not brittle. However, being metastable, they cannot be hot-formed.
One class of amorphous metals, known as Metglas and produced by Allied Corp., contains base metals such as iron, nickel, and chromium alloyed with metalloids like carbon, phosphorous, boron, and silicon.Some of the alloys have yield strengths above 650,000 lb/in2 (4,500 MPa) and fracture toughness better than high-strength steels. The material is
produced in the form of wire, ribbon, and strip. Typical ribbon dimensions are 11/2 in (4 cm) wide and between 0.001 and 0.0025 in (0.02 and 0.063mm) thick.
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Last Updated ( Monday, 23 June 2008 )
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