Study On Preparation And Properties Of Cu/Ti₂AlC Functional Graded Materials

The research and development of skateboard material at electric locomotive is adifficult problem over a long period of time. This study designed a new type ofCu/Ti₂AlC functional graded materials, having good electrical conductivity and frictionproperties. The material has a small thermal stress in use process, good toughness andstrength. With good mechanical properties and excellent oxidation resistance, it canmeet the use requirements of pantograph slide material at electric locomotive indifferent environment. The main content of this paper is as follows:The performance of different Cu/Ti₂AlC composite materials is studied in thispaper. Through control different parameters such as different holding time, differentsintering temperature, different ratio and pressure, and testing the density, hardness,friction coefficient, resistivity and XRD, the good performance material is obtained. Thestudy provides the reference for the preparation of Cu/Ti₂AlC functionally gradientmaterials. Results show that sintering temperature for1h and30MPa pressure,sintering temperature of950℃can get good performance material. And increasingTi₂AlC content, hardness increasing, the relative density is reduced, the resistivityincreases, the friction coefficient reduce.Cu/Ti₂AlC functional graded materials of4layers are prepared through hotpressing. From rich Cu layer to rich Ti₂AlC layer, the structure of material changegradually. Lamellar Ti₂AlC distributes in the network of Cu uniformly. Along with theincrease of the content of Ti₂AlC, mesh structure of Cu disappear gradually, intolamellar and granular distribution. By observing the material layer and morphology ofthe interface, no crack can be found at the interface between the layer and layer withdifferent composition. There is no clear interface, combined with close together. Layerconnects adjacent layer through the mutual diffusion between, and interface betweenCu-20Ti₂AlC layer and Cu-40Ti₂AlC layer is almost not visible. From Cu-5Ti₂AlC toCu-60Ti₂AlC, resistivity, hardness and friction coefficient decreases, and theantioxidant properties improves. The performance of material improves in sintering athigh temperature. Materials have good thermal shock resistance. It is easy to corrode inacid solution, and almost no corrosion occurs in alkali solution. Temperature field and stress field of Cu, composite material of2layer, gradedmaterial of3layers and graded material of4layers is analyzed with finite elementanalysis using ANSYS software simulating the actual working analysis of the pure.Temperature field of Graded material is a gradual transition inside the material. Thetemperature at one side of rich Cu changes smoothly, temperature of rich Ti₂AlC sidehas large change. The more the gradient layers is, the better the temperature moderationis. Stress intensity increased with the increase of graded layers decreased. The stressmainly concentrated in the interface between the layers, and the more layers are,maximum stress and stress area is smaller, and the more obvious stress relaxation is.