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In this paper, CuCr–Zr alloys prepared by vacuum melting with adding La and Ni elementswere heat-treated and aged, followed by plastic deformation using low-energy cyclic impact tests, to simultaneously improve their mechanical and electrical properties. Results showed that the grain size of the casted Cu–Cr–Zr alloys was significantly reduced after the solid-solution aging and plastic deformation process. There were a lot of dispersed Cr and Cu5Zr precipitates formed in the alloys, and the numbers of dislocations were significantly increased. Accordingly, the hardness was increased from 78 to 232 HV, and the tensile strength was increased from 225 to 691 MPa. Electrical conductivity has not been significantly affected after these processes. The enhancement of overall performance is mainly attributed to the combined effects of solid-solution hardening, fine grain hardening, and precipitation/dislocation strengthening.

W–Cu composites, as a traditional material, have attracted tremendous research interest in fields such as electric engineering, electronic information, aerospace, weapons, etc., owing to their excellent properties. This critical review presents and discusses the current development of W–Cu composites. After introduction of the synthesis methods for W–Cu composites, including the conventional and modern preparation approaches, we focus on the description of the improvement of mechanical properties and arc-erosion properties by modification techniques. Finally, the advantages of W–Cu composites in applications such as electrical contacts, electronic packaging materials, and heat sinks, as well as military materials, are described.

Power is an important parameter for mechanical design, processing parameter optimization and motor design. A power model is established for medium equipment (aircraft, steamship, cutting machine, etc.) based on specific cutting energy and material removing rate (MRR). A group of turning experiments were carried out on aluminum alloy 6061 to validate the established power model. The specific turning energy varies with the rotation speed (cutting speed) undulately, and it decreases with increase in the feed per revolution and cutting depth. The MRR increases with the turning parameters. The power increases with increase in the turning parameters due to the larger MRR, although the specific turning energy decreases with the decrease in the turning parameters. The turning power can be classified as kinetics power and stress power. The power efficiency increases with the increase in the turning parameters.

In this paper, arc ablation behavior of tungsten–copper (WCu) alloy contacts was investigated by the measurement of weight-loss, or erosion rate, and microstructures of tungsten–copper alloy contacts were examined by using scanning electron microscopy after electrical breakdown process. Experimental results showed that the arc erosion process started at the tiny sharp edges, then the arc spreaded on the second phases, or copper phase on the surface. Because of electrons/ions bombardment, the rapid evaporation and sputtering of liquid copper droplets were serious. As a result, an even contact surface became rugged, and tungsten skeleton remained because of being less eroded. With the increase of applied breakdown voltage, the ablation of tungsten–copper alloy became more significant. The WCu alloys with a higher content of copper showed more severe erosion rate as compared with that with a higher tungsten content under the same erosion conditions. Furthermore, when the number of breakdown is less, WCu alloys with a high copper content are easier for erosion for the conditions of fewer numbers of breakdowns. Whereas, WCu alloys with a high content of tungsten are easier for ablation for the conditions with many times of arc breakdown.