Mg Based Bulk Metallic Glasses with high Mechanical Strength and Large Viscoplastic Forming Capacity

摘要

Grain size refinement is a well known technique to improve mechanical properties of metallic alloys. Fine grained materials can be produced by recrystallization after severe plastic deformation or thanks to rapid solidification techniques. At high enough cooling rates from liquid state, amorphous alloys can even be produced. In this case, the "liquid" structure is preserved down a critical temperature for which it is frozen. Up to 80's, to avoid primary crystallization, very high cooling rates were required, leading to metallic glasses only under the form of ribbons. Today, thanks to appropriate compositions, bulk metallic glasses (BMG) can be produced. These materials exhibit attractive mechanical properties, in particular high strengths and large elastic domains at room temperature.