An overview of macroscopic and microscopic processing defects that can arise in hot powder extrusion of aluminum matrix composites is presented and their origins are discussed. Some of these defects include microcrack formation in the matrix, fir tree defect, piping, funnel formation and oxidation of matrix powders. Lubrication conditions, usage of aluminum cans, extrusion temperature and ram speed will affect the surface quality of the products.

Investigating the effect of Al2O3-TiB2/Fe complex reinforcement (CCMR) on the mechanical properties of aluminum composites was the goal of this study. For this purpose, the Al2O3-TiB2/Fe reinforcement powders were synthesized during milling and subsequent annealing. Different volume percentages of the produced reinforcement powders (1.25, 2.5 and 5 vol.%) were added to aluminum matrix, milled for 10 h and then hot extruded. The structural phasic and mechanical investigations of the specimens were carried out using X-ray diffraction, scanning electron microscopy and tensile test. The results showed that the metallic component (Fe rich phase) in this new type of reinforcement stuck the ceramic parts (Al2O3-TiB2) to aluminium matrix, and has an importance role in the flexibility of the product. The best volume percentage of CCMR in aluminium matrix was about 2.5%. This nanocomposite had a combination of strength and ductility of about 500 MPa and 6%, respectively.

Aluminum matrix composites reinforced with Al2O3 and SiC particles (5 Vol %) were produced using the hot powder extrusion method. Extrusion temperature and extrusion reduction in area were chosen in the range of 500 to 600°C and 90 to 95%, respectively. The physical and mechanical properties of the extruded composites such as density, tensile strength, elongation and microhardness were evaluated and discussed as a function of extrusion parameters. The microstructure and fracture surface of the products were examined using SEM. The results showed that the composites were fully densified and reinforcement particles were distributed uniformly in the matrix. Presence of Al2O3 and SiC particles increased both strength and microhardness, but decreased the ductility of the composites. Experimental results for hot extrusion of the compacted powder billets also showed that the extrusion pressure was dependent on the ram speed or deformation strain rate.

The physical, mechanical and tribological behavior of Aluminum (Al) alloy LM13 reinforced with Nanosized Titanium Dioxide (TiO2) particulates were investigated in this study. The amount of nano TiO2 particulates in the composite was varied from 0. 5 to 2% in 0. 5 weight percent (wt. %) increments. The Al-LM13-TiO2 Metal Matrix Composites (MMCs) were prepared through the liquid metallurgical method by following the stir casting process. The different types of Al LM13-TiO2 specimens were prepared for examining the physical, mechanical, and tribological characteristics by conducting ASTM standards tests. Microstructural images, hardness, tensile, and wear test results were used to evaluate the effect of TiO2 addition on Al LM13 samples. Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and X-Ray Diffractometer (XRD) were used to examine the microstructure and distribution of particulates in the matrix alloy. In the Al LM13 matrix, microstructure analysis indicated a consistent distribution of reinforced nanoparticles. The attributes of the MMCs, including density, hardness, tensile strength, and wear resistance, were improved by adding up to 1 wt. % TiO2. Fractured surfaces of tensile test specimens were examined by SEM studies. The standard pin-on-disc tribometer device was used to conduct the wear experiments,the tribological characteristics of unreinforced matrix and TiO2 reinforced composites were investigated. The composites’ wear resistance was increased by adding up to 1 wt. % of TiO2. The wear height loss of Al LM13-TiO2 composite increased when the sliding distance and applied load were increased. Overall, the Al LM13 with one wt. % of TiO2 MMCs showed excellent physical, mechanical and tribological characteristics in all the percentages considered in the present study.

Aluminum matrix composites reinforced with nano MgO have been considered in specific industries due to its favorable properties such as strength and resistance to high temperatures. In this study, in addition to investigate the most effective parameters such as temperature and volume percent of reinforcement phase, aluminum foil method (in order to improve the existing problems in the production process) and use of MgO particles in nano scale can be as innovation in this paper. Al-nano MgO composites were manufactured via Vortex method. In order to produce these composites, MgO nanopartic1es with 60-80 nanometer diameter and A356 Al alloy were used as reinforcement and matrix, respectively. The molten composites were stirred for 13 minutes, and then cast into a metallic mold. The effects of MgO volume percent with 1.5, 2.5 and 5 %, and casting temperature (various temperatures, 800, 850 and 950oC) on microstructure of composites were investigated. The results revealed a homogenous distribution of MgO nanoparticles within the metal matrix. Although, MgO agglomerates are observed within the matrix, they are distributed homogenously.

In this study, aluminum matrix composites reinforced with Al2O3 and SiC nanoparticles, and graphene nanoplatelets produced by Spark Plasma Sintering (SPS) were studied. The microstructural and mechanical properties of the composites were evaluated by changing the amounts of the reinforcing materials. The SEM images showed that the reinforcing particles were more distributed in the grain boundary regions. According to the results, the addition of alumina and SiC to the matrix caused an increase in the composite density whereas the composite density decreased by adding graphene nanoplatelets. The highest relative density of 96. 3% was obtained for the composite containing 2 wt% Al2O3. The presence of the reinforcing particles increased the hardness of all the samples compared to the pure aluminum (39 HV). The composite containing 1 wt. % Al2O3, 0. 7 wt. % SiC, and 0. 3 wt. % graphene showed the highest hardness of 79 HV. Moreover, the plastic deformation of the specimens decreased and the slope of the plastic region increased by adding the reinforcing particles to the matrix.

Metal composites have received attention from various industries due to their excellent properties, such as a high strength-to-weight ratio and wear resistance. However, due to the presence of hard and abrasive particles, the challenges have always faced machining. Therefore, studying the effective parameters in the machining of these materials is very important. Drilling is one of the most common and widely used methods in the industry. In this study, the Response Surface Method (RSM) and Central Composite Design (CCD) were used to model, optimize, and analyze the effects of machining parameters. Aluminum composite with AL356 alloy reinforced with 25 micrometers of silicon carbide and 45 micrometers of mica mineral, as well as a 6 mm diameter carbide drill, were used for the experiments. According to the results, with an increase in the drilling speed, the drilling forces increased and the surface roughness decreased. Additionally, increasing the feed rate increased forces and surface roughness. With an increase in the volume fraction of SiC reinforcing particles, the drilling forces and surface roughness increased and decreased, respectively. By analyzing the data obtained from the experiments, the best combination of values was found to minimize the surface roughness and axial force at the same time. The best combination of parameters was found to be: a spindle speed of 1855 rpm, a feed rate of 50 mm/rev, and a weight percentage of 15% SiC

Recently, high-performance lightweight materials with outstanding mechanical properties have opened up their way to some sophisticated industrial applications. As one of these systems, aluminum matrix composites/nanocomposites (AMCs) offer an outstanding combination of relative density, hardness, wear resistance, and mechanical strength. Until now, several additive manufacturing methods have been developed for fabrication of 3D metallic components among them, selective laser melting (SLM), electron beam melting (EBM), laser metal deposition (LMD), Wire+Arc additive manufacturing (WAAM), and ultrasonic additive manufacturing (UAM) are of prime significance. Unlike other methods, in ultrasonic additive manufacturing, the ultrasonic waves are used instead of applying the sintering process. This technique is well-known for its ability to produce 3D components by repeating the alternative welding and machining procedures at low temperatures. This is why it can overcome the technological issues arisen from the high-temperature sintering. The present review strives to provide an inclusive introduction to the principles of ultrasonic additive manufacturing method and recent advances in ultrasonic additive manufacturing of aluminum matrix composites/nanocomposites. Also, the challenges of this new emerging technique, i. e. its dependence to the applied weld power, is addressed in the paper. The authors attempt to give some perspectives to the researchers for further investigations in this new-emerging field.

Metal matrix composites are bunch of materials that have wide range of uses such as construction, abrasion, and heat. This type of composite exhibits better dimension than the base metal such as temperature applications, strength, rigidity, thermal conductivity, wear resistance, creep resistance and stability. In this study, the methods of producing aluminum composite reinforced with ceramic particles, especially the processes of sever plastic deformation, have been investigated. The main focus of this research is to study the microstructure, mechanical properties and mechanisms governing this type of composite produced by two ARB and cross CARB methods. The results of the research showed that in the initial passes of the processed composites there is no proper distribution of reinforcing particles but by increasing the number of passes, the particle distribution is improved and the reinforcing particles are distributed in longitudinal and transverse directions. Tensile strength and microhardness have the same trend which they gradually increased with increasing strain rates and improvement of particle distribution but elongation at first decreased in the initial passes due to the inappropriate distribution of the particles, porosity and cluster particles, and then improved with the elimination of these imperfections and distribution. However, the mechanical and microstructural properties of the CARB method are more favorable. Also, the governing mechanisms for microstructure modification in produced composites by rolling processes are the formation of the Orowan loop, role of reinforcing particles, difference in the coefficient of thermal expansion of the matrix and reinforcement, and so on.