Effects of Nb2O5 Content on Microstructures and Mechanical Properties of Ti(C,N)-Based Cermets Fabricated by In-Situ Carbothermal Reduction Method
The in-situ carbothermal reduction method was used to fabricate Ti(C,N)-based cermets,and the effects of Nb2O5 on microstructures and mechanical properties of Ti(C,N)-based cermets were studied.The results indicate that when the content of Nb2O5 increases from 0%to 2.80%,the hard phase grains of the cermets are significantly refined,and the number of"white core/gray rim"grains increases.Moreover,room-temperature transverse rupture strength(TRS),hardness,critical thermal shock temperature difference,and high-temperature TRS increase,while the fracture toughness decreases.As Nb2O5 content rises,there are holes in the microstructure of the cermets,and room-temperature TRS,hardness,critical thermal shock temperature difference,high-temperature TRS,and fracture toughness gradually decrease.The cermets with Nb2O5 content of 2.80%exhibit the best comprehensive mechanical properties,with a room-temperature TRS of 2 439 MPa,a hardness of 90.6HRA,a fracture toughness of 12.8 MPa·m1/2,a critical thermal shock temperature difference of 360℃,and a high-temperature TRS of 1 519 MPa,respectively.
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