Nickel-based alloys, referred to as the most difficult-to-cut materials, pose a great challenge to cutting tool materials due to their excellent high-temperature properties. Ceramic tools have the potential to improve the machinability of these alloys with the advance of toughening mechanisms. In this work, the wear mechanisms of SiC whisker-reinforced alumina and Sialon when high-speed turning Inconel 718 alloy under dry cutting condition were investigated. The results showed that the wear process of Al₂O₃-SiC_w WG300 was dominated by the notch wear, while the flank wear characterized by ridges and grooves perpendicular to the cutting edge was the main wear mode for Sialon SX9. A Ti−enriched belt was found at the boundary of the wear band for both ceramic tools. The SEM inspection and EDS analysis for this belt suggested the trace of diffusion between the workpiece material and tool matrix. As for the notch formation, the periodically adhesive action of the workpiece material at the depth-of-cut line combined with the thermal shock resistance of ceramic tools were considered to account for its formation. In addition, the oxidation of the workpiece material at the depth-of-cut line played a positive role in reducing the adhesive affinity and consequent notch wear.

BAW-based micromixers usually achieve mixing enhancement with acoustic-induced bubbles, while SAW-based micromixers usually enhance mixing efficiency by varying the configuration of IDTs and microchannels. In this paper, bubble-enhanced acoustic mixing induced by standing surface acoustic waves (SSAWs) in a microchannel is proposed and experimentally demonstrated. Significant enhancement in the mixing efficiency was achieved after the bubbles were stimulated in our acoustofluidic microdevice. With an applied voltage of 5 V, 50 times amplified, the proposed mixing microdevice could achieve 90.8% mixing efficiency within 60 s at a flow rate of 240 μL/h. The bubbles were generated from acoustic cavitation assisted by the temperature increase resulting from the viscous absorption of acoustic energy. Our results also suggest that a temperature increase is harmful to microfluidic devices and temperature monitoring. Regulation is essential, especially in chemical and biological applications.

FeNCN is a potentially fast-charging sodium ion anode due to the presence of lots of broad tunnels and its high electronic conductivity. However, FeNCN has been rarely investigated due to its complicated synthetic process and unclear synthetic mechanism, which affect the precise control of its phase and crystallinity. In this work, phase- and crystallinity-controlled FeNCN polyhedrons grown on nitrogen-doped carbon (FeNCN/NC) are successfully fabricated by adjusting the growing time and temperature. Moreover, the synthesis mechanism is disclosed in this paper. High-crystallinity FeNCN grows along the [001] direction, which exposes sufficient broad channels on the {010} planes and significantly improves the diffusion rate of sodium ions. Moreover, high-crystallinity FeNCN exhibits higher mechanical strength, which reduces its pulverization rate and endows it with durable cycling stability. When applied as an anode in a sodium-ion battery, high-crystallinity FeNCN/NC exhibits a high rate capability of 332 mA h g⁻¹ at 5.0 A g⁻¹ and a stable cycling performance of 368 mA h g⁻¹ after 300 cycles at a high current density of 1.0 A g⁻¹. This work confirms that the sodium-ion storage performance of FeNCN can be further improved by tuning its crystallinity.