研究了TiC、TiN、Tic+TiCN+TiN和TiC+Al_2O_3涂层硬质合金BK6和10K8在车削和铣削45号钢和y8钢时的切削性能。结果表明,镀TiC+Al_2O_3和TiC+TiCN+TiN复合镀层的硬质合金(1255)具有最高的切削性能。对单层涂层切削性能低的原因进行分析后,确定了复合涂层形成时结构的优化途径。例如,在TiC涂层中,碳化物晶粒的尺寸沿厚度向表面增大,并可能超过基体硬质合金碳化物 The cutting performance of TiC, TiN, Tic + TiCN + TiN and TiC + Al_2O_3 coated cemented carbide BK6 and 10K8 on turning and milling 45 steel and y8 steel was studied. The results show that the cemented carbide (1255) with TiC + Al_2O_3 and TiC + TiCN + TiN composite coatings has the highest cutting performance. After analyzing the reason of the poor cutting performance of the single-layer coating, the optimization of the structure of the composite coating was determined. For example, in a TiC coating, the size of the carbide grains increases toward the surface along the thickness and may exceed that of the matrix cemented carbide