[en] Gigacycle fatigue tests were conducted on high-strength steels that contained large amounts of MnS and which had been subjected to different working ratios. Anisotropy was also investigated by fatigue testing in both the longitudinal and transverse directions. The fatigue strengths were positively correlated with higher working ratios, revealing that high working ratios improved fatigue strength. Anisotropy was also observed, indicating that the fatigue strengths in the longitudinal direction were higher than those in the transverse direction. The fracture mode was internal fractures, mostly originating from MnS inclusions. The MnS showed long slender shapes under high working ratios. The inclusion sizes were inversely correlated with working ratios, with small inclusion sizes seen under high working ratios. The inclusion sizes were smaller in the longitudinal direction than in the transverse direction. These results were analyzed by using a prediction derived in the previous study. The results showed the effect of working ratios to be explained by inclusion size. There was little difference between MnS and oxides in that both inclusions revealed almost identical effects when the inclusion sizes were comparable. Anisotropically, some other factor than inclusion size slightly affected the fatigue properties, reducing the fatigue strength in the transverse direction.

[en] We measured the near-field infrared response of MnPS₃ in bulk, few-, and single-layer form and compared our findings with traditional far-field vibrational spectroscopies, a symmetry analysis, and first-principles lattice dynamics calculations. Furthermore, trends in the B_u mode near 450cm^–1 are striking, with the disappearance of this structure in the thinnest sheets. Combined with the amplified response of the activated Ag mode and analysis of the A_u + B_u features, we find that symmetry is unexpectedly increased in few- and single-sheet MnPS₃ due to a restoration of the threefold axes of rotation. Monoclinicity in this system is therefore a consequence of the long-range stacking pattern and temperature rather than local structure.

[en] The hot-press-forming (HPF) steels might contain a few MnS inclusions, and their brittle characteristics and stringer shape can deteriorate the impact toughness and formability. In this study, effects of shape and orientation of MnS particles on Charpy impact and bending properties of 1470-MPa-grade HPF steel sheets were investigated by conducting ex situ three-point bending or tension tests. According to direct observations of sequential cracking processes of MnS particles in the longitudinal-oriented specimen, largely elongated (high-aspect-ratio-valued) MnS particles were prone to form cracks at low strains. In the transverse-oriented specimen, MnS/matrix interfaces were debonded at the lower strains, and were liable to develop into cracks along the longitudinal direction. These observed results in this study indicated that the MnS cracking and MnS/matrix interfacial debonding were major fracture-initiation sites in the longitudinal- and transverse-oriented specimens, respectively, thereby leading to the decreases in both Charpy impact and bending properties in the MnS-containing HPF steel sheet.

[en] Short communication

[en] We demonstrate digital and analog devices with an Ag/MPS₃/Au structure based on layered MPS₃ (M = Mn, Co, Ni) 2D materials. All devices show the bipolar behavior of resistive switching. In addition, Ag/MnPS₃/Au and Ag/NiPS₃/Au devices show synaptic characteristics of potentiation and depression. The digital and analog characteristics of resistance states enable Ag/MPS₃/Au devices to work as both binary memory and artificial synapse devices. The Ag/MPS₃/Au memory devices are promising for applications of flexible eye-like and brain-like systems on a chip when they are integrated with photodetectors and FETs composed of full MPS₃ materials. (paper)

[en] The effects of manganese and sulfur contents and slab reheating temperatures (SRTs) on the magnetic properties of non-oriented semi-processed electrical steel sheets were investigated. The core loss W15/50 of the steels increases with an increase of sulfur content in each steel with different manganese contents, while, the magnetic induction B50 hardly changed with an increase of the sulfur content at any manganese level. The SRTs affect the core loss in steels without hot band annealing, and in steels processed at an SRT of 1273 K showed the lowest core loss. Steels with higher sulfur content processed at an SRT of 1523 K showed deterioration of the core loss caused by the retardation of the grain growth at the recrystallization annealing by the fine MnS (ca.0.1 μm in diameter)

[en] The evolution behaviors of MnS inclusions during 1473 K heating have been systematically investigated for EH36 shipbuilding steel with Zr addition. It is revealed that heating promotes MnS precipitation on the surfaces of ZrO₂ inclusions. Further, quantified results by confocal scanning laser microscopy indicate that the area fraction of MnS first increases, reaches a maximum value, and undergoes a sharp decrease, which corresponds to the three unambiguously defined stages, namely, coarsening, Ostwald ripening, and crushing.

[en] Stainless steels usually contain inclusions, which are known to affect their corrosion behaviour in mild aqueous chloride solutions. The life of the stainless steel components is severely affected as the MnS inclusions dissolve and lead to pitting corrosion. Here, the pits, being local heterogeneities, are studied by a micro probe technique called scanning electrochemical microscopy. To study the effect of inclusions on pitting, type 304L stainless steel samples with different inclusion ratings were scanned at different applied potentials of + 100 mV, + 300 mV and + 360 mV (Ag-AgCl reference electrode) at scan steps of 3.2 μm in electrolyte solutions of 0.1 N NaCl. The results show that, as the applied potential and number of inclusions increases, the corrosion of the material increases as indicated by higher current. (author)

[en] The influence of monovalent impurity (lithium) on the kinetics of manganese sulphidation has been studied as a function of temperature (800-1000 deg. C) and sulphur pressure (1-10⁴ Pa) using microthermogravimetric technique. It has been found that the incorporation of lithium atoms into the growing sulphide scale on manganese decreases the rate of the reaction of about two orders of magnitude. These results are in quantitative agreement with theoretical predictions following from the Hauffe-Wagner theory of alloy oxidation

[en] Examination in the electron microscope of various mixtures of MnS and Y₂S₃ after heating confirms the existence and structures of the phases MnY₂S₄ and MnY₄S₇. It also reveals the existence of at least one phase intermediate between these two, viz, Mn₂Y₆S₁₁ whose structure is an ordered intergrowth of the other two intermediate phases. Low proportions of Y₂S₃ produce isolated brace113brace twin planes in a β1 type matrix, and these tend to aggregate into thin lamellae (domains) of MnY₂S₄. Thus the twin plane is a structural unit in all cases (as previously forecast), and may occur in an ordered or disordered fashion. The necessity for a 'cation-vacancy' model is therefore minimized, or even eliminated. (author)