Bi-modal particles are used as reinforcements for Cu-matrix. Nano TiC and/or Al₂O₃ were mechanically mixed with Cu particles for 24 h. The Cu-TiC/Al₂O₃ composites were successfully produced using spark plasma sintering (SPS). To investigate the effect of TiC and Al₂O₃ nanoparticles on the microstructure and mechanical properties of Cu-TiC/Al₂O₃ nanocomposites, they were added, whether individually or combined, to the copper (Cu) matrix at 3, 6, and 9 wt.%. The results showed that titanium carbide was homogeneously distributed in the copper matrix, whereas alumina nanoparticles showed some agglomeration at Cu grain boundaries. The crystallite size exhibited a clear reduction as a reaction to the increase of the reinforcement ratio. Furthermore, increasing the TiC and Al₂O₃ nanoparticle content in the Cu-TiC/Al₂O₃ composites reduced the relative density from 95% for Cu-1.5 wt.% TiC and 1.5 wt.% Al₂O₃ to 89% for Cu-4.5 wt.% TiC and 4.5 wt.% Al₂O₃. Cu-9 wt.% TiC achieved a maximum compressive strength of 851.99 N/mm². Hardness values increased with increasing ceramic content.

The present work studies the mechanical alloying, consolidation, evaluation, modeling, and optimization of the Al-TiC composites mixed at different milling times (MTs) of 6, 12, 24, and 48 h and reinforced with three TiC concentrations (3, 6, and 12 vol.%). The Al-TiC composites formed via the powder metallurgy method. The XRD of the mixed powder and the consolidated composites were investigated. Furthermore, density, wear, compressive strength, and hardness have been examined for the consolidated composites. Also, the worn surface of the wear-tested composites was studied utilizing SEM analysis. The response surface methodology (RSM) was involved to clarify the effects of mechanical alloying parameters of MTs and the TiC concentrations and their interaction towards achieving their optimum process factors to produce Al-TiC composites. The RSM results prove the applied factors’ importance in improving the consolidated composites’ properties. The optimization results show the optimum parameters to produce Al-TiC composites are 28.4 MTs and 12 vol.% TiC to produce Al-TiC composites with 304.4 ± 3 MPa compressive strength, 191.21 ± 2 HV hardness, 2.88 ± 0.008 g/cm³ density, and 9.7 ± 0.01 mg weight loss. The ANOVA analysis reveals that the suggested models can virtually expect the tested responses of density, hardness, compressive strength, and weight loss with a confidence level of over 90, 98, 95, and 95%, respectively.

The effect of grapheme-nanosheets (GNs) on the mechanical properties and microstructure of the S390 HSS alloy was investigating. The S390 HSS sample reinforced with 0.25, 0.5, and 0.75 wt.% GNS. Powder metallurgy technique was used to prepare all samples. The elemental powders of the alloy were milled in a planetary ball mill by 10:1 ball to powder ratio with speed 350 rpm for 48 hours, and the mixed powders were warm compacted by the uni-axial press at 550◦C under 500 MPa and then sintered in a vacuum furnace at 1370◦C for 1 hour. X-ray diffraction shows the formation of secondary carbide phases and martensite. The density result indicates the decreasing of density values by GNS additions. The mechanical properties show an increase in the hardness and wear resistance by increasing the graphene content. The specimens are metallographically examining using Scanning Electron Microscopy (SEM), and also the electron backscatter diffraction shows a good distribution of GNS in the HSS matrix.

Al-TiC nanocomposites are prepared by powder metallurgy technique. The effect of milling time and TiC percent on the mechanical properties and microstructure are studied. Nano TiC powders with 5, 10, and 20 wt. % is added to the Al matrix. The mixed powders are mechanically milled by a 35:1 ball to powder ratio and 110 rpm for 6, 12, 24, and 48 hr. milling time (MT). Mixed powders are compacted by a uniaxial press under 600 Mpa and sintered at 600 °C for 1 hr. in a vacuum furnace. According to Archimedes’ principle, the density was estimated, which indicated it is decreasing for 6 hr. milling time, followed by an increase for 12 and 24 hrs., then another decreasing for 48 hrs. The addition of nano TiC increases the density values gradually by increasing its percent. Both the phase composition and microstructure of both composite powders and sintered samples are examined using XRD & FE-SEM, respectively. XRD results indicated forming the aluminum carbide (Al4C3) phase that is formed during the sintering process. The microstructure shows the homogeneous distribution of TiC on the Al matrix and the reduction of Al particle size by increasing both milling time and TiC percent. Hardness, compression strength, and wear resistance are improved by increasing TiC content and MT up to 24 hours. Al-20 wt. % TiC composite with 24 hr. milling time exhibited the highest hardness (196.5667 HV) and the lowest wear rate (0.001 g/min).

Cu-(TiC/Al2O3) nanocomposite was synthesized successfully using the powder metallurgy route. The constituents are first ball-milled and then sintered using the spark plasma sintering technique. The tribological and physical properties are investigated. The homogeneity and of ceramics distribution were also evaluated using SEM and XRD. Results showed that TiC and Al2O3 nanoparticles were homogeneously distributed all over the Cu matrix. Copper reinforced with 3 wt.% Al2O3 and hybrid (3 wt. % TiC and Al2O3) had the lowest relative density (95 %). The hybrid (3 wt. % TiC and Al2O3) sample had a higher wear rate value (1.7 * 10-3) at 25 N load, while the sample reinforced with 3 wt.% TiC had the lowest value (0.5 * 10-3) at 25 N load. Cu-Al2O3 exhibited a higher hardness value (149 HV). The highest electrical and thermal conductivities are recorded for the Cu -TiC that were (20.76 MS/m) and (149.03 W/m. k) respectively.