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This study investigates the magnetocaloric potential of the Al50Cr21-xMn17+xCo12 (x=0, 4, 8 at%) high-entropy alloy (HEA) series using integrated experimental and theoretical approaches. Structural analysis by X-ray diffraction and scanning electron microscopy indicate a dual phase containing B2 and body-centered cubic (BCC) structures. Magnetic characterization shows an approximately linear decrease in saturation magnetization and Curie temperature with increasing Cr content. Curie temperatures calculated by Monte Carlo simulations suggest that the measured magnetic properties originate from the B2 phase rather than the BCC phase. The enhanced magnetocaloric effect with decreasing Cr content highlights the attractiveness of HEAs in magnetocaloric applications., QC 20240314

Polycrystalline silicon (poly-Si) significantly expands the properties of the ICT miracle material, silicon (Si). Depending on the grain size and shape and grain boundary structure, the properties of poly-Si exceed what single-crystal (c-Si) and amorphous (a-Si) silicon can offer, especially for radio frequency (RF) applications in microelectronics. Due to its wide range of applications and, on the one hand, its theoretically and technologically challenging microstructure, poly-Si research is the most timely (Ding et al 2020 Mater. Charact. 161 110174; Zhao and Li 2019 Acta Mater. 168 52-62). In this report, we describe how we simulate and analyse the phenomena and mechanisms that control the effect of poly-Si deposition parameters on the structure of the deposited poly-Si films using classical molecular dynamics simulations. The grain shape and size, degree of crystallinity, grain boundary structure and the stress of poly-Si films are determined depending on the growth temperature, temperature distribution in the growing film, deposition flux, flux variation and the energy transferred to the film surface due to the deposition flux. The main results include: (i) the dependence of the crystallinity profile of the deposited poly-Si films on the stress, temperature and the different parameters of the deposition flux, (ii) growth modes at the early stages of the deposition, (iii) interaction and stability of seed crystallites at the early stage of the deposition of poly-Si films and the transition from the isolated crystallite growth to the poly-Si growth, (iv) interplay of the temperature, crystallinity, crystal shape and heath conductivity of different Si phases, (v) four different stages of crystallite growth are described: nucleation, growth, disappearance and retardation.

In order to facilitate the prediction of some physical properties, we propose several simple formulas based on two parameters only, the metallic valence and metallic atomic radii. Knowing the composition, for single-phase alloys, the average parameters can be calculated by the rule of mixture. The input parameters can be obtained from tabulated databases. Adopting from the literature the results of Coulomb crystal model for metals and single-phase high-entropy alloys, we have derived formulas for the shear modulus (G) and the cohesion energy (Ecoh). Based on these parameters separately, we set up two formulas to estimate the hardness in the case of pure metals. For single-phase (solid-solution) HEAs, by simplifying the Maresca and Curtin model, we obtained a formula for estimating the hardness, which takes into account the atomic misfit in addition to G. The maximal hardness for single-phase HEA is approximately 600 kg/mm2 and is obtained for a composition with a valence electron concentration of approximately 6 divided by 7., QC 20240626