Elastic loading of a metallic glass as a method to obtain defined enthalpy states

• Applicant: Professor Dr. Robert Maaß
• Subject Area: Mechanical Properties of Metallic Materials and their Microstructural Origins
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 466247278

Defined thermo-mechanical protocols are a key to target specific microstructures and therefore properties. Such knowledge is used in daily industrial operations to obtain a desired mechanical performance of crystalline metallic materials. Modifying the structure, and therefore mechanical properties of disordered metallic materials, also known as metallic glasses (MGs), is much less straightforward due to the lack of well-defined structure-property relationships. Furthermore, the lack of apparent length scales in the amorphous MG makes it very difficult to identify a given structural state. Therefore, we normally use the measure of stored excess enthalpy to characterize the structural state. In this proposed research project, we want to address this shortcoming by i) homogeneous rejuvenation via stresses within the elastic regime, and ii) by demonstrating how spatial correlation lengths of property fluctuations at different length scales directly quantify a given excess enthalpy state. This will be achieved by using site-specific characterization methods at the micron- and nanoscale. Our planned experiments will reveal saturation limits of rejuvenation, from which we can construct a thermo-mechanical deformation map on how to prepare well-defined and quantifiable structural states. If successful, this research project will introduce a novel structure-property relationship for tailoring properties of MGs.

• DFG Programme: Research Grants
• International Connection: Switzerland
• Co-Investigator: Professor Dr. Heinz Sturm
• Cooperation Partner: Professor Dr. Peter M. Derlet