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effect of milling ball size on the densification and optical properties of transparent y2o3 ceramics - sciencedirect

effect of milling ball size on the densification and optical properties of transparent y2o3 ceramics - sciencedirect

In this study, we report highly transparent Y2O3 ceramics fabricated by hot-pressing only at 1500C without a HIP treatment, featuring in-line transmittance levels of 77% and 84% at a wavelength of 400 and 1100nm, respectively with the grain size suppressed to 710nm. The effect of the ball size during the grinding of Y2O3 powders on the correlation between the thus-prepared Y2O3 powders and the optical properties of the hot-pressed samples is demonstrated for the first time. With a decrease in the diameter of the ZrO2 balls from 5mm to 1mm, the milling efficiency was enhanced and admirable transparency of Y2O3 was attained at a short milling time. However, several micron-sized pores remained in the transparent specimens prepared with 1mm balls, originating from the inhomogeneously packed region of the green body. Finally, the 2mm was found to be optimum for obtaining a fine-grained and pore-free microstructure with the best in-line transmittance of Y2O3 ceramics.

batteries | free full-text | effect of ball milling on the electrochemical performance of activated carbon with a very high specific surface area | html

batteries | free full-text | effect of ball milling on the electrochemical performance of activated carbon with a very high specific surface area | html

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preparation of tizrnbta refractory high-entropy alloy powder by mechanical alloying with liquid process control agents - sciencedirect

preparation of tizrnbta refractory high-entropy alloy powder by mechanical alloying with liquid process control agents - sciencedirect

Liquid process control agents (PCA) were used in TiZrNbTa RHEA powder mechanical alloying.Compared to solid or no PCA, liquid PCA improved the recovery ratio from 5 to 90%.Liquid environment improved the homogeneity of the elemental distribution.Few amorphous phase and C/O interstitial contamination can be effectively avoided.

The development and applications of refractory high-entropy alloys (RHEAs) have garnered attention for their outstanding strength at both room and elevated temperatures and their high resistance to radiation. However, certain issues have posed difficulty in its preparation and resulting quality. Thus, this study proposed and verified a method to improve the quality of RHEA powders prepared by mechanical alloying by adding liquid process control agents (PCAs). Mechanical alloying was investigated without a PCA and with solid (stearic acid) and liquid PCAs (ethanol and n-heptane). The results showed that the liquid PCAs effectively mitigated cold welding. Relative to those of the powders processed without a PCA or with a solid PCA, the recovery ratio of the powders with liquid PCAs significantly increased, i.e., from 5% to 90%. Moreover, the powders produced with liquid possessed an ideal composition similar to that of the designed product. Adding a liquid PCA did not alter the processes of morphology evolution, element inter-diffusion, and structural transformation. The liquid environment increased the efficiency of the particle refinement and element diffusion, thus increasing the homogeneity of the elemental distribution. The presence of the amorphous phase and C/O interstitial contamination were minimal, owing to the maximum limiting value of lattice defects caused by the shear force in the liquid environment. Therefore, the liquid PCA improved the quality of RHEA powders prepared by mechanical alloying.

tailoring the structure and mechanical properties of graphene nanosheet/aluminum composites by flake powder metallurgy via shift-speed ball milling - sciencedirect

tailoring the structure and mechanical properties of graphene nanosheet/aluminum composites by flake powder metallurgy via shift-speed ball milling - sciencedirect

Graphene nanosheet (GNS)/aluminum composites were fabricated via shift-speed ball milling (SSBM), consisting of a long-term low-speed ball milling (LSBM) and a short-term high-speed ball milling (HSBM). During the early stage of LSBM, Al powders were flattened into flakes, while the agglomerated GNSs were gradually dispersed onto Al flakes. After an inflection point of LSBM time, the dispersed GNSs got re-agglomerated and seriously damaged due to the accumulated work-hardening of Al flakes. During HSBM, the GNS/Al flakes were cold-welded into lamellar-structured particles, preserving the GNS dispersion states. It was demonstrated that the 0.5vol.% GNS/Al composites via SSBM with 6h LSBM had proper combination of ultrafine-grained Al matrices with well-preserved, uniformly-dispersed GNSs. Exceptional properties were achieved with a good ductility of 13.5% at a tensile strength of 295MPa. Therefore, such flake powder metallurgy via SSBM proved to be a smart and effective fabrication strategy for nano-reinforced metal matrix composites.

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