Duplex α/β-SiAlON ceramic cutting inserts(30α∶70β)were synthesized by microwave sintering.The effects of solid solution parameters(m,n,z),synthesis temperature,and amount of excess Y2O3 synthesis additive on phase assemblage,microstructure,mechanical properties,and cutting performance were systematically investigated.It was found that increasing m value could improve the formation of α phase while high z value over 1.0 resulted in the dissolution of α phase into β phase and intergranular phase.Increasing the amount of excess Y2O3 could promote densification and elongated β grain growth;however,the excess Y2O3 amount above 4 wt％resulted in substantial crystallization of Mss phase,thus declining the mechanical properties and wear resistance.The microwave-synthesized α/β-SiAlON cutting insert with modified parameters(m=1.7,n=1.0,z=0.7,and 3 wt％excess Y2O3)was obtained with optimal comprehensive properties,whose tool life was found to increase by approximately 75％in high-speed milling of Inconel 718 superalloy compared to the commercial α/β-SiA1ON cutting insert.