Friction Stir Processing (FSP) was used as a cladding method. Al2024 and Al2024-ZrB_2 clad layers were cladded on Al 1050 by three intersecting FSP passes. ZrB_2 powder with a particle size range of less than 20 µm was used as the reinforcement for the fabrication of composite clad layers. Microstructural investigations of clad layers were conducted by Field-Emission Scanning Electron microscopy (FE-SEM). Tensile properties and hardness of clad layers were measured by microhardness and tensile test. In order to study the tribological properties under 3 and 6 N loads, pin on disc wear and roughness tests were performed. Microstructural studies showed that by increasing the number of intersecting passes more homogeneous structure with more uniform distribution of reinforcement particles was achieved. The highest values of microhardness and tensile strength was obtained in clad layers fabricated by three intersecting passes of FSP. The microhardness values of Al2024 clad layer and Al2024-zrB_2 composite clad layer were 100 and 140 HV, respectively. Tensile strength of Al2024 clad layer was 291 MPa while that of composit clad layer was 317 MPa. Wear properties of clad layer fabricated by FSP was remarkably improve compared to Al1050 substrate and best wear properties were achieved in composite clad layer obtained from three intersecting passes FSP.

Al-TiB2 particulate metal matrix composites were fabricated by Accumulative roll bonding (ARB) up to seven cycles. Reinforcing particles were prepared in three different processing conditions: TiB2(as-received), Al -TiB2 (mixed) and Al -TiB2 (in-situ). mixed TiB2- Al powder was produced by milling of TiB2 with Al powder and the in-situ TiB2- Al powder was prepared by mechanical alloying (MA) of Al-Ti-B powder mixtures with various composition of 10, 20 -and 30wt.% Al. in- situ synthesized TiB2- 20wt%Al was selected as the optimum powder. Scanning electron microscopy (SEM) distribution Reinforcing particles, bonding and porosity. Transmission electron microscopy (TEM) was used to show and evaluate the Al grain size of the produced composites. The composite obtained from Al -TiB2 (in-situ) powder showed the most uniform distribution of TiB2 particles and exhibited the highest tensile strength of about 177 MPa in comparison with the composites reinforced with the TiB2(as-received) (156 MPa) and Al -TiB2 (mixed) powder (160 MPa). After seven ARB cycles, an ultra-fine grained structure with the average size of about 300 nm was obtained in the composite reinforced with Al -TiB2 (in-situ) powder. The appearance of dimples on tensile fracture surfaces revealed a ductile-type fracture in the produced composites.

 NiAl intermetallic compound was synthesized by mechanical alloying (MA). Multi-walled carbon nanotubes (CNTs) were distributed in Ni50Al50 powder mixture by different approaches. MAed powders were sintered by spark plasma sintering (SPS) process. Morphology and microstructure of powder particles and sintered samples were studied using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM). Microhardness testing was carried out on bulk samples. Room temperature fracture toughness of sintered nanocomposites was determined by indents provided by Vickers microhardness indenter. The results showed that the addition of carbon nanotubes and the addition approach can affect the Ni-Al reaction, morphology and mechanical properties of nanocomposites. In the first approach; Addition of carbon nanotubes after the formation of NiAl compound, resulted in the reduction of hardness and fracture toughness, while in the second approach; addition of 0.5wt% carbon nanotubes after 15h milling of Ni and Al, increased the rate of Ni-Al reaction and improved the hardness and fracture toughness in comparison with the pure matrix. Crack bridging of carbon nanotubes and their pull out were identified as the predominant toughening mechanisms.

: The aim of this work has been evaluation of photocatalytic properties of TiO2 particles containing amorphous nickel-molybdenum(NiMo)particles synthesized by sol gel process. Amorphous NiMo powder was produced by mechnical alloying. Mechnical alloying process was done by two different nominal compositions namely, N80Mo20 and Ni65Mo35 and under two different milling speeds of 400 and 600 rpm. TiO2 particles containing different amounts of amorphous NiMo particles (0,5,10,20 wt. %) was synthesized by sol gel method(enough amount of NiMo powder was add to the sol) . Microstructural evolution during mechanical alloying and after sol gel and heat treatment was investigated by X-ray diffractometery(XRD). Morphology and microstructure of the powders at different stages were studied by scaning electron microsccopy (SEM) and Energy Dispersive Spectroscopy (EDS). Photocatalytic activity of TiO2 samples was quantified in term of photodegradation of methyl orange (MO).The results of photocatalytic degradation of MO solution over various types of the titania photocatalysts containing different weight percent of NiMo alloyed powders showed the highest efficiency for pure TiO2. According to the results, adition of amourphous NiMo particles to titaniaphotocatalyst caused a reduction in photocatalytic activity.