The Microstructure and Wear Resistance of a Copper Matrix Composite Layer on Copper via Nitrogen-Shielded Arc Cladding
A TiN and TiN·Ti2Cu reinforced copper matrix composite layer was cladded onto a T3 copper substrate to improve the anti-wear performance of copper products by means of the nitrogen-shielded gas tungsten arc cladding method (N2-GTAC). Better than the traditional preparation method of TiN, the TiN particles in the cladding layer were in situ generated using N atoms of shielding gas and Ti atoms of pre-deposited metal powders. In addition, the composite phase TiN·Ti2Cu occurred in the cladding layer, which also had a positive effect on anti-wearing. As Ti increased, the amount and grain size of TiN·Ti2Cu and TiN increased as a result. The hardness of the cladding layer increased with the increasing amount of reinforced phase generated in the layer. The hardness of the layer reached a maximum of 410 HV, which is nearly 5.1 times greater than that of copper. The TiN·Ti2Cu- and TiN-reinforced phases improved the wear resistance of the cladding layers. The cladding layer with 15 wt % Ti had the longsest launch stage (600 s) and the lowest fiction coefficient (0.56).
COPPER MATRIX COMPOSITES REINFORCED WITH TITANIUM NITRIDE PARTICLES SYNTHESIZED BY MECHANICAL ALLOYING AND SPARK PLASMA SINTERING
Copper matrix composites containing ceramic particles such as carbides, borides, or nitrides have attracted much attention over the last few years. The increased interest in such materials has mainly been created by their high electrical and thermal conductivity, good mechanical and tribological properties, and microstructural stability. Among other nitrides, the titanium nitride seems to be considered asan attractive reinforcement due to its high hardness, excellent electrical conductivity, and stability at high temperatures. Moreover, its good corrosion resistance proves the uniqueness of the TiN particles above any other nitrides. In this work, Cu-10 wt.% TiN composite powders were produced by mechanical alloying and sintered by the spark plasma sintering (SPS) technique under different temperatures. The morphology and powder particle size after mechanical synthesis were inspected by a scanning electron microscopy (SEM) for all of the powder samples; chemical composition analyses (EDS) were also  performed. The hydrostatic method was used to measure the density of the composite samples to analyze the influence of milling time on the process of consolidation in the composite powders.
CONSOLIDATION AND PROPERTIES OF Cu-TiC COMPOSITE BY A REDUCTION SINTERING AND COLD EXTRUSION PROCESS
In the present study, titanium carbide (TiC) reinforced copper (Cu) composite was fabricated via powder metallurgy route. Cu-TiC powder mixture was prepared by a high-energy planetary ball milling process for 2h with TiC content varied from 1 to 5 wt%. The powder mixtures were then cold compacted at 200 MPa and sintered at 900C for 2h. After sintering, sample were subjected to cold extrude and then characterized. The results obtained show that relative density decreases when TiC content increased. Result also shows significant improvement of wear resistance at higher TiC addition. An enhancing in tensile strength was observed at less than 2 wt% TiC, larger dose reduces tensile strength of the material. The higher TiC content, the lower electrical conductivity was recorded. Cold extrusion had improved mechanical properties and electrical conductivity of the material.