Challenges Toward the Further Strengthening of Sheet Steel

Ushioda, Kohsaku; Takahashi, Jun; Takebayashi, S.; Maeda, Daisuke; Hayashi, Kenji; Abe, Yasuhito

doi:10.1007/978-3-642-17665-4_23

Cited by 3 publications

(2 citation statements)

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“…The multiphase microstructure is effective for simultaneously improving the conflicting requirements of strength and ductility, and thus, is expected to be further applied to the development of steels with even higher strength-ductility combinations to meet the never-ending demands for lighter and safer steel structures. 3) However, the amounts and compositions of the constituent phases are dependent on each other, being restricted thermodynamically by the composition of the steel and the heat treatment temperature. Thus, the design of multiphase steels having higher strength and higher ductility is not easy or straightforward for monolithic steels.…”

Section: Introductionmentioning

confidence: 99%

Development of Multilayer Steels for Improved Combinations of High Strength and High Ductility

2014

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Multilayer steels have been developed to provide a novel route to achieving higher-performance steels by employing a high-strength steel and a high-ductility steel independently in the layer structure. In this article, a background to the development, design, fabrication, properties, and applications of multilayer steels are overviewed. Multilayer steels exhibit improved combinations of strength and ductility compared with existing monolithic steels and also excellent deformation behaviors under high-strain-rate deformation as well as good formability. Those improved performances of multilayer steel are achieved by increased interfacial toughness between the layers and decreased thickness of the brittle steel layers according to the fracture toughness of the brittle steel and the strength of the ductile steel. The concept of multilayer steels is extended by applying different combinations of components, such as Mg-steel multilayer composite.

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Section: Introductionmentioning

confidence: 99%

Development of Multilayer Steels for Improved Combinations of High Strength and High Ductility

2014

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“…3 Also, the accompanying increase in the maximum tensile stress due to the Si addition resulted in a significant increase in the work hardening coefficient. 4 The physical origins of all these phenomena, however, have not been fully resolved yet.…”

Section: Introductionmentioning

confidence: 99%

Mechanical properties of Fe-rich Si alloy from Hamiltonian

et al. 2017

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The physical origins of the mechanical properties of Fe-rich Si alloys are investigated by combining electronic structure calculations with statistical mechanics means such as the cluster variation method, molecular dynamics simulation, etc, applied to homogeneous and heterogeneous systems. Firstly, we examined the elastic properties based on electronic structure calculations in a homogeneous system and attributed the physical origin of the loss of ductility with increasing Si content to the combined effects of magneto-volume and D0 3 ordering. As a typical example of a heterogeneity forming a microstructure, we focus on grain boundaries, and segregation behavior of Si atoms is studied through high-precision electronic structure calculations. Two kinds of segregation sites are identified: looser and tighter sites. Depending on the site, different segregation mechanisms are revealed. Finally, the dislocation behavior in the Fe-Si alloy is investigated mainly by molecular dynamics simulations combined with electronic structure calculations. The solid-solution hardening and softening are interpreted in terms of two kinds of energy barriers for kink nucleation and migration on a screw dislocation line. Furthermore, the clue to the peculiar work hardening behavior is discussed based on kinetic Monte Carlo simulations by focusing on the preferential selection of slip planes triggered by kink nucleation.npj Computational Materials (2017) 3:10 ; doi:10.1038/s41524-017-0012-4 INTRODUCTION Mechanical properties of alloys originate from the behavior of electrons and atoms on the microscopic scale; however, the strength of atomic bonding does not directly relate to macroscopic mechanical properties such as the yield strength, fracture toughness, and fatigue resistance. This is because the microstructure on the mesoscale, which is composed of various defects such as impurities, grain boundaries, and dislocations, mediates or enhances the response of alloys against external forces, leading to fairly nonlinear and multiscale phenomena. Facing such a nonlinear nature associated with the strength and plastic deformation of alloys, identifying the controlling factors for the mechanical properties is a significantly difficult task, and clarifying the underlying physics at different length and time scales still remains a major challenge in materials science.The authors of the present article took up the challenge of this complicated problem with their particular theoretical and computational tools unique to each characteristic scale range. These tools are electronic structure calculations, the cluster variation method (CVM) of statistical mechanics, and molecular dynamics (MD) simulations, which may cover the atomic to mesoscopic scale ranges. By virtue of high-performance computers, some of the results obtained by the present calculations achieve a higher precision and reveal a clearer picture than those obtained by ordinary experiments.Among the various mechanical properties, the main focus of the present study is the solid-solut...

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