Tantalum–tungsten alloys have been widely used in different industrial sectors—for example, in chemical, medical, aerospace, and military equipment. However, they are usually difficult to cut because of the large cutting force, rapid tool wear, and poor surface finish during machining. This paper presents the machining performance and cutting tool wear of AlCrN/TiAlN-coated carbide tools during the milling process of Ta-2.5W. The effects of cutting parameters on the cutting forces and surface roughness of AlCrN/TiAlN-coated carbide tools were obtained and analyzed. The results show that the wear resistance of AlCrN-coated tools is better than that of TiAlN-coated tools, and that the main wear mechanisms of both cutting tools are crater wear, adhesive wear, and diffusion wear. Compared to TiAlN-coated tools, AlCrN-coated tools reduced the cutting forces by 1% to 15% and decreased the surface roughness by 6% to 20%. A cutting speed within the range of 80–120 m/min can ensure a low cutting force while maintaining good surface roughness, which is more conducive to machining Ta-2.5W.

This paper presented a feasible quantitative method to evaluate carbon emissions of the remanufacturing process of a used vehicle CVT (Continuously Variable Transmission) gearbox. The carbon emission evaluation method is proposed, which is combined with the Hierarchical Relevance Analysis (HRA) theory and the Emission Factor Approach (EFA). In this research, the characteristics of the carbon emissions of remanufacturing process for a used vehicle CVT gearbox are analyzed, various carbon sources on the remanufacturing system are classified and analyzed to define the boundaries of the remanufacturing system, and the correlation matrices among the hierarchical essential factors of carbon emissions are established. Then it combined with EFA to calculate the carbon emissions of each carbon source for the used vehicle CVT remanufacturing process. Finally, the proposed method is experimentally verified by using laser repairing of a used CVT wheel, and the feasibility of new quantitative evaluation method for carbon emissions on the remanufacturing processes is presented. The results show that the carbon emissions of the equipment/device are main contributors of the total carbon emissions of the remanufacturing system. Furthermore, scanning speed of the laser has a significant influence on the carbon emissions of the device and overall carbon emissions of the remanufacturing system.

Due to its inherent high hardness, strength, and plasticity, tantalum–tungsten (Ta-W) alloy poses a considerable challenge in machining, resulting in pronounced tool wear, diminished tool lifespan, and suboptimal surface quality. This study undertook experiments utilizing uncoated carbide tools, TiAlN-coated carbide tools, and AlTiN-coated carbide tools for machining Ta-2.5W alloy. The investigation delved into the intricacies of surface temperature, tool longevity, and the distinctive wear characteristics under varying coating materials and cutting parameters. Concurrently, a comprehensive exploration of the wear mechanisms affecting the tools was conducted. Among the observed wear modes, flank wear emerged as the predominant issue for turning tools. Across all three tool types, adhesive wear and diffusion wear were identified as the principal wear mechanisms, with the TiAlN-coated tools displaying a reduced level of wear compared to their AlTiN-coated counterparts. The experimental findings conclusively revealed that TiAlN-coated carbide tools exhibited an extended tool lifespan in comparison to uncoated carbide tools and AlTiN-coated carbide tools, signifying superior cutting performance.