About this Research Topic
Advanced engineering materials with superior mechanical properties are strongly desired in modern society. Among various kinds of materials, nanostructured metallic materials with nanocrystalline and ultrafine-grained (UFG) structures have drawn much attention over the last decades due to their excellent mechanical properties. Such bulky and condensed materials can be conveniently processed by various severe plastic deformation (SPD) techniques. Though high strength is readily achieved in SPD processed materials, ductility (especially uniform elongation) is low, which can be detrimental for industrial applications since good ductility and toughness are also required in addition to high strength. Unfortunately, strength and ductility trade off in most cases, so conquering the puzzle and bottleneck becomes a critical issue.
Concerning the strength-ductility tradeoff relationship, it is critical to balance strength and ductility or optimize them simultaneously. It is also valuable to optimize the long-term performance of nanostructured materials by eliminating the structural and thermal instability. Scientists around the world have been designing advanced structures, and fortunately, intriguing strategies and results have been reported recently. For example, various kinds of nanostructures including fully recrystallized nanostructure, heterogenous nanostructure, gradient nanostructure, harmonic nanostructure, etc., have been developed in various metallic systems, which exhibit excellent tensile properties, fatigue properties, wear resistance, hydrogen embrittlement resistance, etc. These novel structures can be conveniently processed by traditional thermomechanical process or recently developed techniques, i.e., electro-deposition, powder metallurgy, friction stir processing (FSP), thermomechanical controlled process (TMCP), SPD and post annealing processes.
In order to discuss recent advancements on nanostructured materials with advanced structures and properties, a wide range of themes are set in this Research Topic. Manuscripts on novel structures, physical properties, fundamental deformation mechanisms and modelling work are welcome, and specific themes are listed below:
1. Hierarchical structures with heterogenous constituents which exhibit large discrepancy on physical properties.
2. Nanostructured metallic materials with fully recrystallized grains.
3. High-entropy alloys or multi-principal element alloys with superior strength and ductility.
4. Unprecedented properties of nanostructured metallic materials.
Besides above-mentioned themes, other original research works closely related to strength-ductility optimization are also welcome.
Keywords: processing, nanostructure, ultrafine-grained structure, strength, ductility
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