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Chemistry LibreTexts

7.5: Amorphous Alloys

  • Page ID
    183336
  • On the left is the structure of polycrystalline sample, and on the right is the structure of liquid or glass. The polycrystalline structure is more geometric while the liquid/glass is random.

    Alloys of metals with more complex stoichiometries can be made in amorphous form by slower cooling from the melt. These alloys have been prepared and studied since the 1960s, and since the 1990s amorphous alloys have been discovered that can be prepared in bulk form at cooling rates on the order of 1 deg/s, similar to the cooling rates of other kinds of glasses.

    Graph showing the strength of a material in MPa against the elastic limit in percentage. Steels and silica have a lower elastic limit but silica is weak while steels can range from weak to strong. Titanium alloys and wood have a greater elastic limit compared to silica and steels. Wood is weak like silica while titanium alloys range from weak to strong, but they are not as strong as steels. Glassy alloys are next in elastic limit and are stronger than steels. Polymers have the highest elastic limit but are weak.

    Currently amorphous metals (marketed under the tradenames Vitreloy and Liquidmetal) are used commercially in golf clubs, watches, USB flash drives, and other applications where very high elasticity, yield strength, and/or wear resistance are needed.

    Year Alloy Cooling Rate (K/s)
    1960 Au75Si24 106 - thin films & ribbons[3]
    1969 Pd-Cu-Si 100-1000
    1980s La-Al-Cu & others 1-100
    1990s Zr-Ti-Cu-Ni-Be ~1 (similar to oxide glasses)
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