About this Research Topic
Advanced structural materials, such as ultra-high-strength steels are essential to the modern world and their continuous innovation is critical in enabling humans to move towards a sustainable future. Among the various strengthening mechanisms, Nanoscale precipitation strengthening has been proven to be the most effective method to enhance properties. The traditional second-phase particles, in general, enhance strength while reducing ductility due to the void formation at the interface between coarse particles and matrix. Nanoscale precipitates can enhance strength without scarifying the ductility and keep a satisfied strength-ductility trade-off due to the tiny size, special interphase interface, and precipitates characteristics. In some cases, the group precipitation of multiple types of nanoparticles may provide a superior combination of high strength, good ductility, good weldability, and relatively low cost.
All experimental variables such as solidification condition, composition, and heat treatment influence the precipitation behavior. Precipitation hardening is the most significant since excess alloying elements from supersaturated solid solution form fine particles which act as obstacles to dislocation movement. A better understanding of the formation of nanoscale precipitates, thermal stability, and the nature of the interaction between nanoscale precipitates and dislocations are of high academic and industrial interest since it provides potential freedom for alloy and thermo-mechanical processing design. The challenges arise due to the tiny size of precipitates and complex aging response caused by multi-components. It is important to determine the chemical composition, crystal structure, and orientation relationship as well as precipitate morphology to understand the precipitation behavior and strengthening mechanisms. Advances in characterization technology have greatly improved our ability to quantify nanoscale precipitation. A variety of relatively new techniques, such as in-situ characterization using SEM, TEM, AFM, synchrotron X-ray, and neutron diffraction during testing have enabled us to make significant strides towards gaining more insights into these basic mechanisms. These coupled with modeling tools enable realistic predictions of material performances and strengthening mechanisms for not only steels but also most of the alloys containing nanoscale precipitates.
As motivated by the unresolved fundamental issues on nanoscale precipitation and promising properties of nanoscale precipitation-strengthened steels and alloys, the Research Topic welcomes articles on, but not limited to, the following list of subjects, calling for either experimental and/or modeling results:
• Alloy design and microstructure control
• Thermodynamic and kinetic of the formation and evolution of nanoscale precipitates
• Mechanical properties and microstructure-property relationships
• Atomistic simulations on nanoscale precipitation
• Characterization of nanoscale precipitates
• Processing methods of nanoscale-precipitation strengthened steels or alloys
• Nanoscale-precipitation strengthening mechanisms
• Progress in nanoscale precipitation-strengthening: the new development in controlling and characterization technologies for nanoscale precipitates and the development of new nanoscale precipitation strengthened steels and alloys
Keywords: nanoscale precipitate, precipitation strengthening, strengthening mechanisms, steels and alloys, mechanical properties
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