Abstract
Nanocomposites are worn resistant materials used in cutting tool applications. The materials are composed of ultrafine powder hard phase grains surrounded by a tough binder phase carbon nanotubes (Mo2C)1-x–(TiC)x (2≤x≤4)//1Wt% SWCNTs. Composite bicarbide Mo2C-TiC was rapidly synthesised and simultaneously consolidated by field activated sintering technique (spark plasma sintering) at which the extensive volume expansion occurred as a function of the volumic fraction from 20 to 40 vol.% of TiC powders and 1 Wt.% of SWCNTs was reinforcement of the NCMC’s. The sintered powder mixture was examined by XRD patterns, the morphology of the obtained phase was observed by SEM and the phase compositions in different regions were analyzed by EDX. The composites were processed using Field Activated Sintering Technique, spark plasma sintering (SPS) at temperatures in the range of 1700-1800°C with addicting of SWCNTs. The effects of SWCNTs addition on phases morphology, microstructure hardness and fracture toughness of the nanocomposite were investigated. The best product contained 1.0 Wt% SWCNTs from (Mo2C)1-x–(TiC)x , x= 0.2 which was sintered at 1700°C, 70 MPa for 10 min, M0.8T0.2/ 1 Wt% SWCNTs exhibit a better density, highest hardness and good ductility. Relative densification was achieved 99.5 % from the theoretical and good mechanical properties like hardness and fracture toughness (KIC=5.6 Mpa m1/2) are improved. The results were confirmed using Raman scattering resonant spectroscopy.
Highlights
Nanomaterials have been the subject of extensive research in recent years due to their extraordinary properties over their conventional counterparts
XRD spectrum of the (NCMC’s), which indicates that the reaction between the titanium carbide (TiC) powders and SWCNTs did happen during the sintering process
X-ray diffraction patterns of sample M1-xTx(2≤x≤4) /1Wt% SWCNTs,M0.8T0.2/1Wt% SWCNTs, (NCMC’s) sintered at 70 MPa pressure were enhanced because they are reinforced with the SWCNTs phases, TiC and SWCNTs with higher intensity, the SWCNTs content at the sintering temperature of 1700 ° C for 10 min at 70 MPa, which was reduced to 10 % when sintered at pressure because it reacted with TiC to produce TiC-SWCNTs, in the TiC grain new intergranular reinforcement slightly increases
Summary
Nanomaterials (defined as being in the size range 1-100 nm in at least one dimension) have been the subject of extensive research in recent years due to their extraordinary properties over their conventional counterparts. A fine (Mo2C)1_x–(TiC)x (2≤x≤4)// powder grade was chosen as the matrix material The use of only 20 vol.% of TiC with 1 Wt% SWCNTs reinforcements aims to increase physical and mechanical resistance of the(NCMC’s). In the case of low temperature SPS sintering process weak bonding between the TiC grains may yield to low micro hardness and high fracture toughness.
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