| Copper alloy due to its excellent physical properties, chemical properties and mechanical properties occupies a very important position in the project materials. Dispersion-strengthened copper composite material is a kind of high-performance copper-based composite materials using high stability, high-strength ceramic particle as reinforcement; it is a particle reinforced metal matrix composites. Its component design, material structure and preparation process are common and unique comparing with traditional particle reinforced metal matrix composites.Particle reinforced metal matrix composites are composed of one or more material particles which uniformly dispersed in the metal matrix. The diameter size, distance between particles and distribution characteristics are directly impacting on enhancment. The diameter of metal matrix composites enhanced particle significantly enhance the effect in a certain range, to ensure that the conductivity of the lower small range.Ti2SnC powder is selected as the strengthen phase in this text. Ti2SnC is the three-element chemical compound of Ti-Sn-C system, it has the good nature of metal, For example, it has good thermal conduction performance and electric conduction performance, good thermal shock resistance properties, easy processing properties and high temperature plastic property at normal temperature.It also has the fine nature of ceramics, such as high yield strength, high melting point, high thermal stability, high-temperature strength, fine oxidation resistance property and corrosion resistance performance. The most importance is that it has the friction coefficient which is lower than graphite, and it also has the better self-lubricating property.By far, there have not the report about preparing Ti2SnC powder of high purity by combining mechanical alloying and vacuum heat treatment. This text plans to prepare Ti2SnC powder of high purity by combining mechanical alloying and vacuum heat treatment technology and researches the influence of preparing technics to the pure of Ti2SnC powder, at the same time, it is searching for the best preparing technics.Preparing Ti2SnC/Cu composite material of high density and searching for the influence of strengthen phase to the organize and performance of composite material.For the ball milling and heat treating powders,we analysis the phase composing of them by using X-ray diffraction instrument of the type of D/Max2500PC, and determine the content of Ti2SnC by using the technique of X-ray quantitative phase analysis; We study the microstructure and the pattern character of sample by using scanning electronic microscope with the type of JSM-5600LV and the energy spectrometer of EDAX-Falcon. For Ti2SnC/Cu,we measure its microhardness by using microhardness equipment with the type of FM-700; and measure its density by using Archimedes principle; measure its frictional coefficient by using machine with the type of UNMT-1; measure its electrical resistivity by using electric transmitting machine with the type of vacuum ZEM-2 from Japan.The researchs show that Ti-Sn-C powder can be composed of the mix powder with some compounds such as Ti2SnC and TiC a by mechanical alloying. Ti2SnC powder with purity quotient greatest can be fabricated under mechanical alloying 10 h with the speed of rotation is 550, the ratio of grinding media to material is 10:1. The purity of Ti2SnC had risen notably by vacuum heat treatment.Ti2SnC/Cu block with high density can be prepared by spark plasma sintering, in low temperature(750℃-950℃). When sintering temperature is 950℃,the relative denseness of Ti2SnC/Cu block can reach 96%.The hardness of composite material are heightening with the increasing of Ti2SnC powder grain.When the content of Ti2SnC reach 10%,the hardness of composite can reach 148 HV which is 1.5 doubles of pure Cu.The friction coefficient of composite reach lowest 0.35,when sintering temperature is 800℃. The friction coefficient of composite decreased when the content of Ti2SnC increased. When the content of Ti2SnC reach 10%,the friction coefficient of composite low to 0.24,which is 0.5 doubles of pure Cu.When the content of Ti2SnC is relative low, the composite conducts electricity is good.As the content of Ti2SnC increased, conductivity of composite deceased fast.But the content of Ti2SnC exceed 10%, conductivity of composite declined slightly. |
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