Study On Preparation And Mechanical Properties Of TiC_x/Ni Matrix Composites By XD Method

Ni and TiC,as its wide application and abundant reserves,is more appreciated.In this paper,we found the TiC/Ni composites are difficult to prepare by consulting literature.So we use Ti3AIC2 as the TiCx preform to explore the preapation process of the TiC_x/Ni matrix composites.In this article,the XRD,SEM,EDS,DSC were used to analyze the reaction mechanism of Ti3AIC2 and Ni,the phase and the microstructure of the composites.Through the material density,microhardness,fracture toughness,cold bending compression test and high temperature bending compression experiment,to explore the reinforcing mechanism of TiCx reinforcing particles and the influence law of process conditions on the mechanical property of material.The results show that:（1）TiC_0.65/Ni-based composites can be successfully prepared by hot-pressing sintering with pure Ni powder and Ti₃AlC₂ powder.（2）Ti₃AlC₂ can reacts with Ni powder below the melting point of Ni（1460℃）.The resultant product is TiCx and Ni-Al.The mechanism of the reaction is that Ti3AlC2 first decomposes to form TiCx and A1 atoms,and then A1 diffuses into the Ni matrix.The sintering temperature will increase the rate of diffusion of A1 into the Ni matrix.（3）The microstructure of TiCx/Ni-based composites is mainly composed of matrix,TiCx reinforced phase and few defects.With the increase of the sintering temperature,the TiCx enhanced phase gradually grows and the defects decrease gradually.With the increase of Ti₃AlC₂ volume,the TiCx enhanced phase distribution is more dispersed.（4）1400℃,TH₃AIC₂ volume fraction of 40%TiCx/Ni composite material has the most excellent mechanical properties at room temperature,the KIC value is 19.25±0.99MPa·m1/2,the compressive strength is 1803±47MPa,the fracture strain is 10.2%± 1.85%,bending strength of 616 ±3 5MPa.This is mainly due to TiCx and Ni have good interfacial bonding strength and excellent microstructure under the sintering conditions.（5）TiCx plays a more significant role in enhancing the composites.The mechanism of toughening is caused by the mechanism of crack deflection,crack bridge and microcrack.The increase of compressive strength is due to the plowing and stacking effect of TiCx on Ni matrix.The high bending strength is due to the dimple formation.These multiple toughening mechanisms,small trenches and dimple formation indicate that the interface bonding strength of TiCx and Ni matrix at room temperature is high.（6）In the high temperature test,the composite material can maintain the compressive strength of 1GPa at 800℃,and the dimple and groove is still found on the fracture surface.It is shown that TiCx and Ni still have satisfactory interfacial bonding strength under high temperature conditions.（7）Ti₃AlC₂ volume fraction has a great influence on the Vickers hardness of the material.The Vickers hardness of TiCx/Ni matrix composites prepared by 40%Ti3AlC2 volume fraction is above 4.2GPa.The density of TiCx/Ni-based composites with the change of the sintering conditions.With the increase of the volume fraction of Ti3AlC2,the density of TiCx/Ni-based composites decreases;With the increase of the temperature,the density standard deviation decreased gradually.