In the current research work, a top-down approach was employed for the refinement of a micron scale AA2124 alloy powder 40 μm in average size using high-energy ball milling up to 60 hours. The produced nanopowders were investigated compared to the micron gas atomized powder both in the monolithic and the reinforced composite states. 1 μm powder of TiC with internal structure <100 nm was used for the reinforcement of the 2124-Al matrices. Milling time of 36 hours produced a <100 nm nanopowders with internal structure size <20 nm. The nanopowder monolithic consolidates exhibited compressive strength of 388 MPa compared to 313 MPa for micronpowder one. Addition of TiC nanostructured powder to the nanopowder consolidated matrix resulted in increase of 130% in compressive strength compared to that produced for the microscale one. Nanopowder of Alalloys produced by mechanical milling reinforced with 10 wt% TiC is recommended for products suitable for high wear and erosion resistance applications. Peak aging increased the hardness and compressive strength of the as compacted micronpowder matrices by an average of 188% and 123%, while increased that of the nanopowder matrices by an average of 110% and 117%, respectively.

Aluminum based metal matrix composites are devoting more interest towards multiple applications due to their good thermal and mechanical properties. At this study, composites of AlMg5/ZrO2 with multiple gradients of ZrO2, were manufactured using stir casting technique. Microstructure, hardness and tribological properties of the composite were investigated. Pin-on-disk technique was used under wet conditions (3.5 wt. % NaCl solution) at different sliding speeds (varied from 0.125 to 0.5 ms -1 ) and applied loads (varied from 5 to 20N). Microstructure and X-Ray Diffraction (XRD) analysis show that the composites AlMg5/ZrO2 were successfully manufactured via stir casting with a uniform distribution of ZrO2 particles. The results revealed that the hardness and wear resistance of the investigated alloy significantly increased by incorporating ZrO2 up to 10 wt.%, beyond this value the hardness and wear resistance diminished but still higher than the base alloy. Further, the outcomes showed that the dominant wear mechanism in AlMg5 alloy and its composite was the abrasive wear.

Friction stir processing (FSP) is a novel solid-state technique based on the principle of friction stir welding. It is used for material processing in order to modify the microstructures and mechanical properties and to fabricate metal matrix composites. FSP has been successfully employed for fabrication of AA6082/ (6, 10, 14, and 18 vol. % / WC) composite materials. Tungsten carbide nanoparticles with an average diameter of 50 nm were added as a reinforcement material. Tungsten carbide particles packed in a groove of width (0.4, 0.7, 1, and 1.3 mm) and depth 5 mm to result in four different volume fractions. FSP experiment parameters like tool rotational/traverse speed, groove width, tool geometry, and number of passes were studied. The mechanical and wear behavior of composite material fabricated by FSP were investigated. The process parameters were optimized using the Taguchi analysis, at last, optimum values of corresponding tests are determined. The results were confirmed by further experiments. The results reveal that ultimate tensile strength, hardness and wear resistance of WC/A6082 nanocomposite are enhanced, compared to those of the AA6082 matrix, and Wear rate significantly decreased after a multi-pass.

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In the present investigation, Al-5Zn-2.5Mg - 1.6Cu -xSn (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 wt. %) alloys were fabricated using melting and casting technique. The microstructures of the alloys were studied using optical, scanning electronic microscope/EDS and X-ray diffraction. The corrosion behaviour was performed using electrochemical measurements and immersion tests while the wear behaviour was carried out by pin-on-disc technique. The findings revealed that incorporating Sn to the Al-5Zn-2.5Mg alloy improved its corrosion and wear resistance due to refining the grains. The corrosion potentials shifted from -884 to -943,-955, -996,-1008 and -1012 mV (Ag / AgCl), while the coefficient of friction declined from 0.69 to 0.62 , 0.51 , 0.34, 0.29 and 0.22 with increment of Sn content from 0.0 to 0.2, 0.4. 0.6, 0.8 and 1.0 wt%, respectively. On the other hand, the results illustrated that the wear rate diminished from 4.42 *10 -3 to 1.47 * 10 -3 (mm3/Nm) with increasing Sn from 0.0 to 1.0 wt%. Furthermore, the findings showed that increment of Sn content stimulated the uniform corrosion on the surface of alloys.