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Metal matrix composites (MMCs) are materials that have a ductile matrix reinforced with a hard ceramic phase. This combination gives advanced mechanical and functional properties, such as high yield and tensile strength, modulus, and wear resistance. [1-4] Therefore, these materials are widely utilized in automotive, aerospace, medicine, and other high-tech industries. Traditionally, MMC materials are fabricated via the powder metallurgy route, where metal and ceramic powders are premixed and then sintered. [5] As the reinforcement phase, carbides, oxides, nitrides, and borides are normally implemented. Due to the rapid development of the additive manufacturing (AM) market, there is a demand for new materials that can be fabricated additively including MMCs. Moreover, MMCs are normally hard to machine adjusting a semiproduct to a final shape. Thus, manufacturing a nearnet-shape MMC product is an attractive solution, which can further promote the introduction of AM techniques. Dadbakhsh et al. [6] reviewed several attempts of MMC manufacturing via laser powder bed fusion (L-PBF) dealing with Al-, Ti-, and steel-based materials. Specifically, Yuan et al. [7] produced AlSi10Mg-5.8 vol% TiC composite material finding the optimal parameters for the sufficient distribution of the TiC-phase during a L-PBF process. Gu et al. [8] fabricated the Ti/TiC composite revealing a dependence of the reinforcement phase shape and its distribution in the matrix on the L-PBF process parameters and TiC content (up to 22.5 wt%). AlMangour et al. [9] investigated 316 L/TiC MMC with varying reinforcement phase content from 2.5 to 15 vol%. These examples describe the ex situ addition of the reinforcement phase to the matrix by mixing metal and TiC powders prior to the printing process. As an alternative, it is possible to fabricate the reinforcement phase in situ bringing needed elements in contact. Tjong et al. [10] summarized the benefits of in situ formation of the reinforcement phase: enhanced thermodynamic stability, strong interfacial bonding, sufficient reinforcement phase distribution, and refinement, which further improve the mechanical properties of MMC. In the recent years, the in situ approach for AM gained much attention among researches. [11-25] For instance, Promakhov et al. [24] produced Inconel 625/TiB 2 MMC material applying self-propagating high-temperature synthesis (SHS). Obtained blocks were grinded to a coarse powder and then plasma spheroidized yielding spherical particles with TiB 2 reinforcements of 0.5-5 μm size. Thereby, this powder was successfully utilized for test samples fabrication by direct laser deposition technique (DLD). AlMangour et al. [12] utilized for L-PBF mechanically alloyed composite powder. For this experiment, 316L-Ti-graphite mixed powders were milled for 35 h

The role of B2O3 as a fluxing agent for developing fluoride-free fluxes has been accentuated in recent years. Therefore, knowledge about the thermophysical properties of the oxide is essential to find the optimal chemical composition of the mold fluxes. In the present study, the density and thermal conductivity of B2O3 were measured by means of the buoyancy method, the maximal bubble pressure (MBP) method and the hot-wire method in the temperature range of 295 – 1573 K. The results are discussed in the context of the chemical stability of the B2O3 as well as the effect of glass transition on the thermal conductivity. The density of the B2O3 decreases non-linearly with increasing temperature in the temperature range of 973 – 1573 K. The MBP method was successfully applied for the density measurements with a viscosity up to 91 Pa.s. The thermal conductivity of the B2O3 in the solid and molten states increases with increasing temperature. Based on the Kittel’s equation, the temperature dependence of the thermal conductivity through the glass transition temperature of B2O3 was discussed.

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Metallic material concepts associated with the sustainable and efficient use of resources are currently the subject of intensive research. Al addition to steel offers advantages in view of lightweight, durability, and efficient use of high-Fe scrap from the Al industry. In the present work, Al was added to Fe-12Cr-(9,12)Ni-3Mn-0.3C-xAl (x = 0.1–6) (wt.%) stainless steels to assess its influence on microstructure and mechanical properties. According to density measurements based on Archimedes’ principle, densities were between 7.70 and 7.08 g/cm3. High-energy X-ray diffraction estimations of the lattice parameter indicated that nearly 31% of density reduction was caused by the lattice expansion associated with Al addition. Depending on Al concentration, austenitic and duplex matrix microstructures were obtained at room temperature. In the presence of up to 3 wt.% Al, the microstructure remained austenitic. At the same time, strength and hardness were slightly enhanced. Al addition in higher quantities resulted in the formation of duplex matrix microstructures with enhanced yield strength but reduced ductility compared to the austenitic alloys. Due to the ready formation of B2-(Ni,Fe)Al intermetallics in the ferrite phase of the present alloy system, the increase in strength due to the presence of ferrite was more pronounced compared to standard duplex stainless steels. The occurrence of B2 intermetallics was implied by dilatometry measurements and confirmed by electron microscopy examinations and high-energy X-ray diffraction measurements.