Bulk Metallic Glass?
Generally, the atoms in an alloy are arranged in an ordered and repeating pattern, known as a crystalline lattice. These crystals can be of various shapes and arrangements, all of which determine the resulting properties of the alloy.
However, no such arrangement is perfect and there are defects in these arrangements (as shown in this figure). These defects and the failure to localize them is the source of mechanical failure or corrosion in alloys. It is often found that alloys in which crystals are larger, they tend to fail more readily than the alloys with small or no crystals.
Bulk Metallic Glasses (BMGs) are a special class of alloys that do not follow any particular order in their atomic arrangement, therefore have no crystalline lattice. These alloys often contain alloying elements with atoms of large variations in atomic radii that inhibits the growth of crystals within the alloy melt. This particular property of BMGs leads to many interesting properties, such as:
High levels of hardness
Improved magnetic permeability
Improved corrosion resistance
Smooth surface finish
Improved bio-compatibility (due to similar structure as bones)
amongst many others.