Bendy Metallic Glasses

At first glance, bulk metallic glasses (BMGs) seem to possess the perfect combination of properties to make metal obsolete. The amorphous alloys are strong, lightweight, inexpensive, and corrosion-resistant. But BMGs have an Achilles' heel: poor plasticity. Under excessive strain, the materials break without warning. Now, Wei Hua Wang and coworkers at the Chinese Academy of Sciences, in Beijing, describe a family of superplastic BMGs that resist such catastrophic failure (Science 2007, 315, 1385). The researchers' ZrCuNiAl glass (shown) bends effortlessly, withstanding a strain of more than 160% at room temperature. Wang attributes the material's unusual deformability to its microstructure, which features tiny islands of hard, structured regions surrounded by soft, disordered areas. He hopes his group's findings will give materials scientists guidelines for making other superplastic BMGs.