In-situ Reactive Synthesis Of Cu-TiB₂ Composite And Its Properties

TiB₂ ceramic particles with high hardness,high elastic modulus,double use of both structural and functional ceramics,as the reinforced phase of Cu matrix composites have attracted much attention.In this paper,the preparation process by in-situ synthesis,physical and mechanical properties of Cu-TiB₂ composites and their tribological properties were studied.Cu powder,Ti powder and B powder were used as raw materials,and Cu-TiB₂ composites were in-situ synthesized by hot-pressing method after ball milling.The reaction process of Cu-Ti-B system was discussed in detail.By means of XRD,SEM,EDS,XPS and so on,to determine Ti and B in the Cu matrix in-situ synthesis of TiB₂.The calibration curve of TiB₂ and Cu was established by means of XRD,and using external standard method to calculate the synthesis rate of TiB₂ under different sintering temperature.The results showed that: in a certain temperature range,the higher the temperature,the higher the synthesis rate of TiB₂,and the synthesis rate of TiB₂ under 1000?sintering temperature was up to 99.27%.Cu-TiB₂ composites were in-situ synthesized by hot-pressing method under different sintering temperature,the influence of sintering temperature on the properties of the composites were studied,the results showed that the Cu-TiB₂ composite block prepared under 1000?sintering temperature has good comprehensive properties.Its relative density,hardness,electrical conductivity,thermal conductivity and three point bending strength were 98.1%,154 MPa,80.01%IACS,293W/mK and 778 MPa,respectively,and its thermal expansion coefficient in the range of 25¹00? was 15.6534×10^-6/K.Cu-TiB₂ composites with different contents of TiB₂ were in-situ synthesized by-hot pressing method under 1000? sintering temperature,and the effects of TiB₂ content on the physical and mechanical properties of composite materials were studied.The results showed that the Cu-2.5wt%TiB₂ composite block prepared under 1000? sintering temperature has good comprehensive performance.The effects of TiB₂ content,load and rotational speed on the friction and wear properties of Cu-TiB₂ composites were also investigated.The microstructure and wear surface morphology of the composites were observed and analyzed by SEM.The results showed that with the increase of TiB₂ content,the friction coefficient decreased and the wear resistance is improved greatly;with the increase of load,the wear rate increased gradually;with the sliding speed increasing,the friction coefficient increased firstly,and then tended to be stable,the wear rate grew.The wear mechanism of Cu-TiB₂ composites was also discussed.