جستجوی مقالات مرتبط با کلیدواژه « aluminum matrix composite » در نشریات گروه « مکانیک »

The use of aluminum with a reinforced coefficient to increase this material compared to aluminum is used in the automotive, aircraft, and locomotive industries. This article examines the parameters of the material removal rate (MRR) rate and surface quality in the machining process of composite aluminum in different percentages of SIC. It examines the machining characteristics of end milling operations to obtain minimum surface quality, cutting force, and chip removal rate with maximum material removal rate using gray relational analysis based on the response surface design method (RSM). Twenty-seven experimental runs were carried out based on the response surface design method (RSM) by changing the parameters of spindle speed, feed, and depth of cut in different weight percentages of reinforcements such as silicon carbide (SiC-5%, 10%, 15%). And alumina (5-5% Al2O3) in the aluminum metal base 7075. Gray relation analysis was used to solve the multi-response optimization problem by changing the weights for different responses based on quality or productivity process requirements. The results show that spindle speed and SiC weight percentage are the most important factors that affect the machining properties of hybrid composites.

Friction stir processing is a solid-state method used for local homogenization, grain structure refinement, and improvement of mechanical properties of metallic materials. Through this method, AA5456/SiO2/5-15p nanocomposites were produced in the present research. The average particle size of the reinforcements was 20 nm. The processing parameters included the constant traverse of 8 mm/min and rotational speeds of 800 and 2500 rpm. The microstructural examinations were carried out using the optical and scanning electron microscopies. The results showed that the average grain size of the stir zone reduced by incorporation of the reinforcing particles into the matrix. It was also observed that the increase in the rotational speed results in a decrease in the grain size of the stir zone. The mechanical properties of the friction stir processed composites were also evaluated by the microhardness and tensile testing. It was revealed that the microhardness is increased from 80 to 170 HV when the rotational speed increases. The tensile test results showed an improved strength from 130 to 210 MPa for samples with lower percentages of reinforcements.

In this article the effect of hot rolling process on properties and microstructure of Al-B4C composite is investigated. To produce the composite samples، 3 vol. % B4C particles with 300 nm average grain size added to melted Al-356 alloy. Rolling process was done at 350 °C on vortex samples that is made after 15 minutes mixing at 850 °C. Porosimetry، hardness and tensile strength tests were carried out to investigate the physical and mechanical properties of composite samples. Microstructures of the samples were also investigated by using scanning electron microscopy. The results indicate lowering the amount of porosity، increasing hardness and increasing tensile strength of rolling composites. The amount of porosity before rolling process was 2. 05% that is decreased to 0. 35% after rolling process. Tensile strength and hardness of composites before and after rolling process achieved 178 MPa and 293 MPa and 62 HBN and 101 HBN respectively. Also hot rolling process caused to more ductile fracture of composites that is produced by vortex. Tensile strength and hardness of composites before and after rolling process achieved 178 MPa and 293 MPa and 62 HBN and 101 HBN respectively. Also hot rolling process caused to more ductile fracture of composites that is produced by vortex.