RT Journal Article A1 Juanjuan CHEN,Jixin CHEN,Hao ZHANG,Minmin HU,Meishuan LI; AD Chinese Academy of Sciences, 110016, 中国 ; University of Chinese Academy of Sciences, 100049, 中国 ; Chinese Academy of Sciences, 110016, 中国 ; Chinese Academy of Sciences, 110016, 中国 ; University of Science and Technology of China, 中国 ; Chinese Academy of Sciences, 110016, 中国 ; University of Science and Technology of China, 中国 ; Chinese Academy of Sciences, 110016, 中国 T1 Microstructure and mechanical properties of h-BN/Yb4Si2O7N2 composites YR 2018 IS 4 vo 7 OP 317-OP 324 K1 microstructure;mechanical properties;h-BN/Yb4Si2O7N2 composites;machinability AB A series of h-BN based composites with Yb4Si2O7N2 as a secondary phase were successfully synthesized by an in situ reaction hot pressing method. It was found that the relative density and room-temperature mechanical properties monotonically increased with increasing the content of Yb4Si2O7N2 from 20 to 50 vol%. When 50 vol% Yb4Si2O7N2 was introduced, the relative density of the composite reached 98.75%, and its flexural strength, compressive strength, fracture toughness, and hardness reached 338±10 MPa, 803±49 MPa, 2.06±0.06 MPa·m1/2, and 2.69±0.10 GPa, respectively. The strengthening effect of Yb4Si2O7N2 was mainly attributed to its high modulus and high hardness. Fine microstructure was also advantageous to strength and could lead to more tortuous crack propagation paths and then improve the fracture toughness of the composites simultaneously. Meanwhile, the composites maintained good machinability. SN 2226-4108 LA EN