Dresden 2017 – wissenschaftliches Programm
MM 69: Topical session: Dynamics, relaxation and deformation in deeply supercooled metallic liquids and glasses VII - thermodynamics and structure
MM 69.2: Vortrag
Donnerstag, 23. März 2017, 17:45–18:00, IFW A
Cryogenic Rejuvenation of Metallic Glasses — •Jonas Lübke, Isabelle Binkowski, Niklas Nollmann, Martin Peterlechner, Harald Rösner, and Gerhard Wilde — Institute of Materials Physics, WWU Münster, Germany
The material class of metallic glasses shows interesting properties such as high strength, toughness and corrosion resistance. However, a severe lack of ductility makes the material unsuitable for many applications. In the past, a lot of work was concentrated on reducing this disadvantage using micro-alloying or crystalline precipitates with notable success. A different approach is the concept of ”free volume” in metallic glasses. The redistribution of present free volume may lead to enhanced ductility. This so called rejuvenation can be achieved by mechanical preloading in the elastic regime. Ketov et al.  claim to achieve this rejuvenation by using the heterogeneous thermal expansion coefficient of metallic glasses to induce internal strain by thermal cycling. To avoid structural relaxation these cycles have to be at cryogenic temperatures. By this the ductility of the metallic glass is said to be improved in a different and simple way. In this contribution effects of different degrees of cryogenic rejuvenation, i.e. change in cycle numbers and resting times at different temperatures, on the metallic glasses Vitreloy1, Pd40Ni40P20 and Pd39Ni41P20 on their amount of free-volume, structural relaxation and mechanical properties are presented and discussed.
 S. V. Ketov et al. Rejuvenation of metallic glasses by non-affine thermal strain. Nature 524, 2015