2016 Sawamura Award (03/10/2016)

Following four papers are awarded the 2016 Sawamura Award.

・ Effect of CaO/SiO₂ Ratio on Surface Tension of CaO・SiO₂・Al₂O₃・MgO Melts【The reason for an award】
ISIJ Int. Vol.55, No. 6, pp.1299-1304
Sohei Sukenaga（Tohoku University）, Tomoyuki Higo（Kyushu University）, Hiroyuki Shibata（Tohoku University）, Noritaka Saito, Kunihiko Nakashima（Kyushu University）
Surface tension of molten slag is one of physical properties which dominates the cohering behavior or interfacial phenomena between heterogeneous phases, and very important for every industrial processes which is concerned with molten slag. On the other hand, experimental data of surface tension of molten slag are not adequate and experimental analysis of surface structure of molten slag is very difficult, so the understanding of the surface tension or interfacial phenomena has been on the developing, yet.
This paper deals with the precise measurement of surface tension of silicate melt, and has clarified the influence of basicity of the melt on its surface tension. Furthermore, it has proposed a new model of surface structure of the melt. This model succeeded in the explanation of the contribution mechanism of bridging oxygen and non-bridging oxygen in the melt to the surface tension without contradiction. The proposed model of the surface structure largely advances the understanding of surface or interfacial properties of molten oxide melt, and are very valuable.

・ Tensile Behavior of Ferrite-martensite Dual Phase Steels with Nano-precipitation of Vanadium Carbides【The reason for an award】
ISIJ Int. Vol.55, No. 8, pp. 1781-1790
Naoya Kamikawa（Hirosaki University）, Masahiro Hirohashi, Yu Sato, Elango Chandiran, Goro Miyamoto, Tadashi Furuhara（Tohoku University）
Ferrite - martensite dual phase (DP) steels, composed of soft ferrite phase and hard martensite phase, are a category of commercially available advanced high strength steels with good combination of high strength and excellent formability. However, one drawback of the ferrite - martensite DP steels is their poor post-uniform elongation due to the large difference in strength between the ferrite and martensite phases. On the other hand, nano-precipitated ferrite steels, which are well known commercial steels, exhibit both high strength and large post-uniform elongation, but suffer from a low work-hardening ability.
Based on a new concept of "nano-precipitated ferrite - martensite DP steels", this paper has achieved high strength and large post-uniform elongation simultaneously in ferrite - martensite DP steels by utilizing nano-sized vanadium carbides formed in ferrite phase through interphase precipitation. In addition, this paper analyzed local strain distribution during tensile deformation precisely by digital image correlation technique, and demonstrated that accumulation of strain in the ferrite phase and early fracture in the martensite phase were prevented by nano-sized vanadium carbides formed in ferrite phase. This paper significantly contributes to both the academic and industrial aspects, and it is worthy of the Sawamura Award.

・ Phase-field Simulation of Habit Plane Formation during Martensitic Transformation in Low-carbon Steels【The reason for an award】
ISIJ Int. Vol.55, No. 11, pp. 2455-2462
Yuhki Tsukada, Yasuhiro Kojima, Toshiyuki Koyama（Nagoya Institute of Technology, Yoshinori Murata（Nagoya University）
In the present paper, using the phase-field method, the authors have succeeded in the simultaneous modeling of the cubic(γ)→tetragonal(α') martensitic transformation with {111}_γ habit plane and the evolution of dislocations with the Burgers vector α_α’ /2⟨111⟩_α’ in the α' phase. One of the most characteristic features of the present paper is that the elastic strain energy associated with both the Bain strain and the slip α_α’ /2⟨111⟩_α’of dislocations is evaluated. From results of the three-dimensional phase-field simulations, the authors have shown that the formation of the {111}_γ habit plane of the martensite phase in low-carbon steels is attributed to the slip α_α’ /2⟨111⟩_α’of dislocations in the α' phase during the martensitic transformation. As shown in the present paper, the phase-field method is a powerful tool in steel research. The paper provided a reliable basis for research on the martensitic transformations that are important to understand microstructures and mechanical properties of steels. Hence, we conclude that it deserves the Sawamura Award .

・ Influence of Refractory-Steel Interfacial Reaction on the Formation Behavior of Inclusions in Ce-containing Stainless Steel【The reason for an award】
ISIJ Int. Vol.55, No. 12, pp. 2589-2596
Sun Kuk Kwon (Hanyang University, MetalGenTech), Jun Seok Park (Hanyang University, KITECH), Joo Hyun Park (Hanyang University)
Addition of cerium(Ce) to stainless steels is known to be effective for the improvement of high temperature oxidation and corrosion resistance. It is important to know the reactions of molten steel with refractories in order to control the inclusions which form in the refining of stainless steels. However, such information on the molten stainless steels including Ce have been limited.
The influence of the reactions of molten steel with refractories made of alumina on the formation of inclusions in stainless steels including Ce has been experimentally investigated in this work. The mechanism of the reactions of molten steel with the refractories has been clarified, which is useful to the control of the formation of inclusions. The oxide phases have been determined by observing the interface between the molten steel and the refractories in detail. It has much academic value that a follow-up survey has been conducted on the variation of the composition of inclusions with time, in particular. Moreover, it is technically evaluate that the effect of Ce on the deoxidation has been systematically investigated, which gives some important pieces of knowledge which contribute to the production of stainless steels with high corrosion resistance.
The paper apparently has an absolute value with an academic and a technical significance, and thus it is worth well the Sawamura Award.