Effects of Nickel Element on Microstructure and Properties of VC Reinforced Iron-base Composite

VC reinforced iron matrix composites were synthesized in situ from FeV powder,Ni powder and graphite powder under sintering temperature of 1 150 ℃ and pressure of 20 MPa.X-ray diffraction（XRD） was used to analyze the phases.Three-point bending strength and Rockwell hardness were tested,and scanning electron microscopy（SEM） was used to analyze the microstructure and fracture morphology.The results show that,due to the stabilization of austenite by Ni,dual phases of α-Fe and γ-Fe appear in the iron matrix when the content of Ni exceeds 6%,with its microstructure of pearlite and austenite.The hardness and bending strength of the specimens increase with the increase of Ni content.When Ni content increases to 9%,the hardness increases from 39 HRC to 43.7 HRC.The bending strength increases from 1 028 MPa to 1 926 MPa,and the fracture mode changes from cleavage fracture to dimple fracture.