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Impact of inclusion size on acicular ferrite formation in EH36 shipbuilding steel weld metal subjected by CaF2–TiO2 flux has been investigated. Findings suggest that the critical size for Ti-containing inclusions nucleating acicular ferrite is approximately 0.28 μm. Effective inclusions are predominantly within the size range of 0.4 to 1.1 μm. Furthermore, nucleation probability shows a positive correlation with inclusion size, increasing from initial less than 10 pct (≤0.4 μm) to almost 100 pct (1.1 μm). [ABSTRACT FROM AUTHOR]

Planar to cellular transition in the EH36 weld metal subjected to CaF2–TiO2 flux has been observed in situ under confocal scanning laser microscope. It is found that planars experience bifurcations, which preferentially evolve into cellular twins at the boundary, extending cellular arrays to interface. It is demonstrated that critical instability rate at the planar boundary is lower than that at the interface. Wavelengths of adjacent cellulars at both boundary and interface follow reverse relations with time. [ABSTRACT FROM AUTHOR]

Kagome materials serve as crucial platforms for investigating the quantum anomalous Hall effect (QAHE) due to the presence of kagome bands in their electronic structures. However, despite the theoretical predictions being proposed, kagome band material realizations have been limited. In this work, through tight-binding (TB) model analysis, by setting the nearest-neighbor hopping integrals with opposite signs, we propose a Yin–Yang kagome band structure characterized by two stable enantiomorphic kagome bands. Furthermore, we design a monolayer V3Cl6 to confirm the TB model. Three V atoms are located in different coordination environments in V3Cl6, so opposite signs of the hopping integrals between two of their orthogonal d orbitals can be achieved, which is the key to realize Yin–Yang kagome band structures. The calculated band structures obtained from first principles are consistent with those from the TB model. Additionally, we find that the two enantiomorphic flat bands in monolayer V3Cl6 possess opposite Chern number after spin–orbit coupling is considered, which can also be confirmed from symmetry index analysis. The Chern numbers as well as the topological properties can be modulated by doping hole or adjusting the magnetization directions, so the QAHE can be tuned in monolayer V3Cl6. Our results provide a practicable pathway for realizing Yin–Yang kagome band structures and achieving tunable QAHE in them. [ABSTRACT FROM AUTHOR]

Al alloying/doping in HfO2-based resistive random-access memory (RRAM) has been proven to be an effective method for improving the low-resistance state (LRS) retention. However, a detailed understanding of Al concentration on oxygen vacancy migration and resistive switching (RS) behaviors still needs to be included. Herein, the impact of Al concentration on the RS properties of the TiN/Ti/HfAlO/TiN RRAM devices is addressed. Firstly, it is found that the forming voltage, SET voltage, and RESET voltage can be regulated by varying the Al doping concentration. Moreover, we have demonstrated that the device with 15% Al shows the minimum cycle-to-cycle variability (CCV) and superior endurance (over 106). According to density-functional theory (DFT) calculations, it is found that the increased operation voltage, improved uniformity, and improved endurance are attributed to the elevated migration barrier of oxygen vacancy through Al doping. In addition, LRS retention characteristics of the TiN/Ti/HfAlO/TiN devices with different Al concentrations are compared. It is observed that the LRS retention is greatly enhanced due to the suppressed lateral diffusion process of oxygen vacancy through Al doping. This study demonstrates that Al alloying/doping greatly affects the RS behaviors of HfO2-based RRAM and provides a feasible way to improve the RS properties through changing the Al concentration. [ABSTRACT FROM AUTHOR]

Microstructural characteristics has been investigated along the weld metal penetration of EH36 shipbuilding steel processed by CaF2–30 wt. pct TiO2 flux under 60 kJ·cm−1 submerged arc welding. It is demonstrated that microstructures have been significantly refined from equiaxed to columnar grain zone, where acicular ferrite morphology varies from plate to lath. Concurrently, the fraction of acicular ferrites is enhanced while that of polygonal ferrites shrinks, enabling a bimodal misorientation distribution towards auspicious properties. [ABSTRACT FROM AUTHOR]

Two-dimensional intrinsic magnetic topological materials that can realize device miniaturization have attracted significant attention recently based on their chiral dissipationless edge states. However, since the experimental observation of quantum anomalous Hall effect (QAHE) is still limited by low temperature, high operating temperature and large nontrivial gap are urgently needed. Here, monolayer MnAsO3 is predicted to be a room-temperature intrinsic magnetic topological material with high Chern number C = 3 based on first-principles calculations, which offers the possibility of achieving high-speed and low-energy-consumption electron transport in the future. Furthermore, the large and experimental feasible nontrivial gap up to 79.09 meV is obtained under compressive strain modulation. Moreover, the high-Chern-number topological phase transition and strain-induced spin-unlocked edge states are observed, indicating the possibility of tuning the electron transport of QAHE. All these findings suggest that monolayer MnAsO3 is a suitable and promising material for fabricating low-energy-consumption spintronics devices. [ABSTRACT FROM AUTHOR]