Research On The Fabrication And High Temperature Mechanical Properties Of TiC/Ni Cermet Composite Material

TiC/Ni cermet composite material has been synthesized by melt in-situ reaction from mixed Ti,C,Mo and Ni powders.Microstructure and phase composition of the cermet were analyzed by scanning electron microscopy and X-ray diffraction respectively.Relative density and hardness were measured.Because there have been a few study on high temperature mechanical properties especially high temperature creep properties on TiC/Ni cermet so far,in this article,a large number of high temperature tensile and creep tests were carried out on TiC/Ni cermet prepared by in-situ reaction on the CSS-3905 electronic creep test machine.at last,the creep damage of the creep specimen was characterized by the method of electric resistance,the method of Rockwell hardness and the method of elastic modulus.Results show that TiC/Ni cermet composite material is mainly consist of metal phase Ni and ceramic TiC,the addition of Molybdenum has effect on refining the size of the particle of ceramic phase;the relative density of TiC/Ni cermet composite material is becoming larger with the increasing of the content of TiC, when the content of TiC is constant,the relative density has a positive proportional to the content of Ni and has nothing to do with the content of the content of Mo.and Rockwell hardness is determinated by the phase compositions and the relative density;the results of the tensile test show that when the content of TiC is low,the mechanism of the fracture is ductile fracture,when the content of TiC is high,the mechanism of the fracture is brittle fracture.When the temperature is increasing,the strength of the material decreases,the strain increases.TiC/Ni with 20% volume fraction of TiC and 5% volume fraction of Mo has the best creep resistance.and the mechanism of creep fracture is intergranular fracture;the feasibility study on the method of electric resistance is verified,the method of Rockwell hardness has something difficult to survey.the method of elastic modulus is well to characterize the creep damage, variations of the curve of damage fator are concordant with variations of the curve of creep at different periods.