Skip to main content

Next generation of complex metallic materials with intelligent hybrid structures

Final Report Summary - INTELHYB (Next generation of complex metallic materials with intelligent hybrid structures)

In modern society, metallic materials are crucially important (e.g. energy, safety, infrastructure, transportation, health, medicine, life sciences, IT). However, the current-state-of-the-art technology is challenged by the performance of conventional materials. Contemporary examples with inherent challenges to be overcome are the design of materials possessing ultrahigh specific strength/stiffness, exceptional corrosion and wear resistance, extremely low magnetic losses, very high resonance, low creep, and enhanced fatigue resistance for long-term use depending on the application field. The present time challenges in clean power generation and other aspects of sustainability are additional utmost important issues requiring new solutions in the form of new materials and new processing routes. To this extent, metallic glasses, high entropy alloys, shape memory alloys, etc. with intelligent hybrid structures will surely have a prominent role in future material developments tackling such issues.

The key concept behind INTELHYB is to define new routes for the creation of tailored metallic materials based on scale-bridging intelligent hybrid structures enabling property as well as function optimization. We have shown that hierarchical patterning of CuZr- and Ti-based metallic glass systems with high accuracy is possible, which can potentially be utilized for customized bioimplant design following the needs of patients. Secondly, the intrinsic properties of advanced alloy systems can be altered by changing their microstructural features. The amelioration and deterioration of the intrinsic properties of materials, i.e. rejuvenation and relaxation, respectively, were assessed on an atomic and global scale by means of different characterization techniques including electron microscopy, thermal analysis, nanohardness measurements, and universal tension/compression.

Furthermore, length-scale effects on the mechanical behavior of porous BMGs were explored. When reducing the size of metallic glass samples, a wide variety of failure modes ranging from brittle to ductile ones were observed. Simulations on the deformation behavior of nanoscale metallic glasses reported unusual extended strain softening and are not able to reproduce the brittle-like fracture deformation behavior found in experiments. Using large-scale molecular dynamics simulations, we provided an atomistic understanding of the deformation mechanisms of PdSi- and CuZr-based metallic glasses and their nanolaminate composites, and differentiated extrinsic size effects and aspect ratio contributions to plasticity. Besides, cost- and time-effective additive manufacturing has been realized for some alloy types, where the obtained properties do not fall behind or even exceed those of conventionally produced materials in terms of mechanical and wear properties as well as the corrosion resistance.

Although various BMG systems were proven to have extensive plasticity (over 20%), so far, no attempts had been undertaken to reveal the main reason for this behavior on the atomic scale. For the first time, we have shown that the primary mechanism behind the formation of softer regions is the formation of homogenously dispersed nanocrystals, which are responsible for the start and stop mechanism of shear transformation zones and, hence, play a vital role in the enhancement of mechanical properties. Finally, hydrogen interactions of Pd-based metallic glasses and a variety of high entropy alloy systems were carefully studied, revealing a remarkable increase in hydrogen sorption kinetics and electrocatalytic activity by adequately adjusting the composition and sample thickness.