Insight on the process ability of bulk metallic glasses by thermo-mechanical analysis and dynamic mechanical analysis

Abstract

Mechanical properties of glassy materials exhibit drastic changes in the supercooled liquid region (SLR). In the current research, mechanical properties in several typical bulk metallic glasses (Pd42.5Ni7.5Cu30P20, Zr56Co28Al16 and Zr58Nb3Cu16Ni13Al10) were measured using both dynamic mechanical analysis and thermo-mechanical analysis. The modifications of elastic modulus (determined by dynamic mechanical analysis) and viscosity (determined by thermo-mechanical analysis) are strongly connected. The experimental findings suggest that the elastic modulus of the bulk metallic glasses evaluated by dynamic mechanical analysis correlates with the length variations determined by thermo-mechanical analysis facilities. Evidences from the experiments demonstrate that the modifications are very important in the bulk metallic glass with a large supercooled region and a large fragility, (Pd42.5Ni7.5Cu30P20), very limited in the bulk metallic glass with a limited supercooled region and a small fragility (Zr56Co28Al16), intermediate in the third case (Zr58Nb3Cu16Ni13Al10). The onset of crystallization corresponds to the end of the deformation of the sample and to the onset of the hardness increase. Therefore, these two different techniques (dynamic mechanical analysis and thermo-mechanical analysis) can provide useful and insightful information on the process ability of these amorphous materials.