The Study Of Preparation And The Properties Of Cu/Ti₃SiC₂ Functionally Graded Material

The temary compound Ti3 Si C2 attracts increasing interest owing to their unique properties in recent years. It has the similar properties of ceramics stiffness exhibiting excellent properties of high-temperature stability, excellent thermal shock resistance、corosion and antioxidation resistance. They are also similar to metals with good thermal and electrical conductivities, even more important, Ti3 Si C2 is an exceptional solid lubricant with an ultra-friction.In this paper, Ti3 Si C2 bulk material was fabricated by vacuum hot press sintering, Ti3 Si C2 fine power particles were obtained by mechanical pulverization, ball-milling. The Cu/Ti3 Si C2 composites with different volume fraction(5%~40%) of Ti3 Si C2 were fabricated by using HP, the optimal preparation process of Cu/Ti3 Si C2 composites technology parameters as follows: 850 °C with 1 h dwelling, the heating rate is 10 °C/min, 30 MPa in vacuum atmosphere. The cross section morphology of the composite gradually transition from mesh to lamellar structure with the increase Ti3 Si C2 volume fraction. We test its density、electrical resistivity、microhardness、friction coefficient、antioxidant、anticorrosion、the flexural strength and fracture toughness. All the experimental results revealed that: when Ti3 Si C2 volume fraction is 5%, Cu/Ti3 Si C2 composites material has the optimal conductive ability, and the density, the flexural strength and fracture toughness reach the maximum, are 98.7%、876MPa、7.4 MPa·m1/2, respectively. When Ti3 Si C2 volume fraction is 40%, the microhardness of the composite reached its maxmum is 3.6 MPa and the coefficient of friction achieve the minimum value is 0.164, composite materials of oxidation and corrosion resistance ability were improved significantly, Cu/Ti3 Si C2 composites material has excellent acid and alkali resistance, the resistance to alkali corrosion was much better than that to acid corrosion.The optimum preparation process of Cu/Ti3 Si C2 functional gradient composite as follows: from the room temperature to 750 °C with 10 °C/min, 1 h insulation, with 5 °C/min to 850 °C, 1 h dwelling. SEM test results show that the combine between the internal layers of the composite is tight. Ceramic particles tightly wrapped in the reticular formation of Cu, it is easy to see the lamellar structure in composites along the direction of the increase Ti3 Si C2. There are a gradient change of hardness values of Cu/Ti3 Si C2 FGM from layers of rich Cu to rich Ti3 Si C2. Constant temperature oxidation study shows that the oxidation kinetics of Cu/Ti3 Si C2 FGM in the temperature range of 600 °C~800 °C for up to 30 h exposure in air followed the parabolic law. Cyclic oxidation study suggests that the oxidation kinetics of Cu/Ti3 Si C2 FGM in the temperature range of 600 °C~800 °C for 15 times also followed the parabolic. Cu/Ti3 Si C2 FGM under 600 °C with excellent oxidation resistance. Thermal shock resistance test results show that Cu/Ti3 Si C2 FGM under 700 °C after 10 times hot cold shock, bending strength from 723 MPa to 436 MPa, due to the gradient change of the internal composition, the internal stresses of the samples are moderated and the interfaces between the layers are close, the surface did not appear obvious cracking phenomenon. The corrosion rates of Cu/Ti3 Si C2 FGM in acid corrosion greater than that immersed in alkali and increase in the alkaline solution. The resistance in alkali corrosion of Cu/Ti3 Si C2 FGM is much better than that in acid corrosion.