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In electrochemical discharge machining (ECDM), continuous renewal of electrolyte between the tool electrode and the workpiece guarantees stable discharge machining. Proposed in this paper is Porous-electrode ECDM (p-ECDM) using a tool electrode made of porous material containing micrometer pores. The rough surface of the porous electrode promotes electrolyte regeneration between the electrodes to produce a stable and relatively thin gas film. At the same time, the internal connected micropores are used to provide controlled gas flow to the processing area, reduce the energy consumption of electrolytic bubbles, and improve the discharge energy to achieve efficient ECDM processing. Experimental results indicate that compared with a solid electrode, the porous electrode has faster electrolyte renewal, smaller bubble volume, more-stable voltage characteristics, 22.55% less overcut, a 4.7% smaller heat-affected zone, and better deep hole processing ability. Experimental results for p-ECDM assisted by controlled airflow demonstrate a 54.23% increase in the material removal rate. [ABSTRACT FROM AUTHOR]

The Ni-GQDs composite plating was created using direct current (DC), single-pulse, and double-pulse power supplies, with GQDs serving as additives under supercritical CO2 conditions. A comparative analysis was conducted to evaluate the effects of different electrodeposition power sources on the microstructure and properties of the Ni-GQDs composite plating. High-Resolution Transmission Electron Microscopy (HRTEM) was employed to investigate the distribution of GQDs within the composite plating as well as to analyze d-spacing and diffraction patterns. Scanning Electron Microscopy (SEM) was utilized to illustrate the surface morphology of the plating and assess its surface quality. The grain size and preferred orientation of the plated layer were examined using X-ray Diffraction (XRD), while Atomic Force Microscopy (AFM) was used to evaluate the roughness of the surface. To compare the abrasion resistance of the various plating types, wear amounts and friction coefficients were measured through friction and wear tests. Additionally, corrosion resistance tests were performed to assess the corrosion resistance of each plating variant. The results indicate that the Ni-GQDs-III composite layers produced via double-pulse electrodeposition exhibit superior surface quality, characterized by smaller grain sizes, enhanced surface flatness, reduced surface roughness, and improved resistance to wear and corrosion. [ABSTRACT FROM AUTHOR]

10CrNi3Mo alloy steel has the characteristics of high hardness and wear resistance, and is widely used in aircraft and spacecraft, shipbuilding and so on. However, its conventional processing method has high tool loss. Wire Electrical Discharge Machining (WEDM) technology is based on electrode pulse discharge to corrode materials. There is no direct contact between the tool and the workpiece, so it is suitable for processing materials with complex shapes, such as high hardness and high brittleness. The focus of this study is to investigate the effects of different electrical parameters such as pulse width, pulse gap, current, and wire feeding speed on the recast layer thickness (RCL) and surface roughness (SR) of 10CrNi3Mo alloy steel processed by wire discharge machining using orthogonal experiments. The gray correlation method was used to optimize the above two process indicators, and seeking optimal processing parameters. The optimized recast layer thickness was 8.65 μ m. The surface roughness is 1.932 μ m. Achieve expected goals. [ABSTRACT FROM AUTHOR]

Zirconia is gradually used in manufacturing aerospace and other fields because of its excellent mechanical processing properties. Due to its hardness and brittleness, zirconia can easily cause excessive and unstable changes in grinding force during machining, resulting in extensive surface damage and poor surface quality. Therefore, it is important to establish an appropriate grinding force model and achieve accurate control and prediction of the grinding force. Ultrasonic-assisted grinding can reduce grinding forces, improve workpiece surface quality, and increase processing efficiency. However, the grinding force model for ultrasonic-assisted grinding is still not adequately investigated. In this study, a new method for predicting the axial force of ultrasonic-assisted grinding is proposed. Vickers hardness and indentation fracture theories combine two different methods: plastic removal and brittle fracture. Moreover, conventional and ultrasonic-assisted grinding tests are performed. Then, the relationship between grinding forces and process parameters is investigated using numerical statistical calculation methods. The grinding force data obtained from the test validate the theoretical model, with the average error between the theoretical and experimental values being 22.87%. The influence of machining variables on the grinding force is investigated, and experimental results of conventional al grinding and ultrasonic-assisted grinding are compared. It is found that the rotary ultrasonic-assisted grinding force can be reduced by up to 66.76%. [ABSTRACT FROM AUTHOR]

To achieve rapid, efficient, and low-cost preparation of large-scale stable aluminum alloy superhydrophobic surfaces, a new preparation method is proposed. The outer surface of the array micro-protrusions was coated with a layer of armor, which was the molten spatter produced during picosecond laser processing. The molten sputters and micro-protrusions combined to form micro–nano composite multi-layer structures. Through these special array micro–nano composite multi-layer structures and chemical modification, the wear-resistant and superhydrophobic properties of aluminum alloy surfaces were realized. According to test results, the array micro–nano composite structures prepared by picosecond laser and chemical modification had a water drop contact angle of 154.6° and a water drop rolling angle of 2°, exhibiting excellent superhydrophobic and anti-adhesion properties. Its self-cleaning, corrosion resistance and friction and wear behavior were systematically analyzed. The analysis results showed that the rolling droplets on the prepared surface could easily take away contaminants. The corrosion voltage and corrosion current density of the prepared superhydrophobic surface are significantly lower than that of the raw surface. In addition, a water drop contact angle of the aluminum alloy sample maintained at 145.1° after five wear tests, indicating the prepared surface after wear testing still had hydrophobic performance. The innovative method proposed in this study provides a simple and effective method for preparing large-scale wear-resistant superhydrophobic surface of aluminum alloy. [ABSTRACT FROM AUTHOR]