The objective of this work is using a hot press technique to join a hybrid structure of aluminum alloy AA6061-T6 sheet of 1mm thickness together with polyamide PA sheet of 2mm thickness. The aluminum alloy specimen was pre-holed with two holes of 5mm diameter. The joining process was carried out with a lap joint configuration. Three different process parameters of the joining process were used: temperature (164, 172 and180°C), pressure (4, 7 and 10 bar) and time (1, 2.5 and 4 min.). The joints were tested by a shear test, macrostructure and scanning electron microscope (SEM) inspection. The design of the experiments (DOE) method was used to analysis the effect of the process parameters on the joint shear force. The DOE optimized the shear force of the joint with a maximum value of 1565 N at 177.5°C 4bar and 3.5min. The SEM examination indicated that the joining mechanism occurred by re-solidified the PA through the internal surface of the aluminum hole.

This research aims to study the effect of RSW parameters on the sheer force of the spot welded for two materials {AISI 304L and AA 6061-T6} with (0.5 and 0.7 mm) thickness. Three values for each welding parameters (welding current, electrode force, squeeze time and welding time) are to be used. The effect of those parameters has been analyzed by using design of experiments (DOE) in order to determine and reduce the number of the tested specimens. The experimental tests have been done that are; shear, micro hardness tests and microstructure examination. It was found that the maximum shear force in welding of similar material AISI 304L is (F = 4.78 KN for t = 0.7 mm), while in the joint of dissimilar material (AA 6061-T6 with AISI 304L), the maximum shear force is (F = 1.42 KN for t = 0.7 mm). These values have been optimized to reach (F =5.13 KN & F =1.54 KN) respectively by using DOE. The minimum shear force was (F = 0.07 KN in t = 0.5 mm). It was found that, increasing the welding current and sheet thickness gave an increase in the shear force, but at the same time the reduction in shear force has occurred during the increasing in electrode force, squeeze time and welding time. From micro hardness tests, it was found that the maximum value of hardness was at the center of nugget zone (NZ) and it reduces slightly until reaching constant values away from nugget zone.

Fuzzy logic is an optimization technique used to predict the behaviour of any problem. Polyethylene (PE) sheet of thickness 3 mm was joined by means of hot press method with aluminium (Al) of thickness 1mm using lap join type. The inside surface of aluminium in the lap joint region was anodized to increase the size of surface pores and mechanical interlock between the melted polymers in the pores of anodized surface of aluminium. The anodizing process was performed by a solution of 15%wt. sulphuric acid with deionized water. The anodizing current density and time were 200A/m2 and 60 min. respectively. The hot press process parameters were; temperature: 115, 125, 135 and 145 °C, pressure: 2, 4, 6, and 8 bar and the pressing time: 1, 2, 3 and 4 min. The hot press method was successfully joined the anodized Al with PE sheet. Shear tensile test was used to estimate the shear strength of lap join. These data are optimized using a fuzzy logic concept which gives a good indication about the effect of input process parameters on the shear of joints. Increasing the applied pressure, decreasing the pressing time and increasing the temperature up to 80 °C resulted in increasing the maximum shear force of joint.

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The purpose of this research is to analyze the mechanical properties and corrosion resistance of spot welding of stainless steels AISI 316L using the process of resistance spot welding varying welding parameters with three level for each of welding parameter; welding current (A.), electrode Pressure (bar), squeeze time (s.), and welding time (s.). The welding current was (4500, 5500 and 6500) A, the electrode Pressure was (20, 30 and 40) bar, the squeeze time was (0.6, 0.8 and 1) Sec., and the welding time was (0.3, 0.6 and 0.9) Sec. The specimens were inspected by a tensile-shear test, corrosion test and the inspection of scanning electron microscope (SEM). The technique of design of the experiments (DOE) was utilized to examine the influence of the welding process parameters on the joint tensile-shear force. The results were analyzed by the DOE method to determine the optimum tensile-shear force, where can be obtained by utilizing the welding parameters by welding current 5500A, electrode pressure of 30 bar, squeeze time 0.8s., and welding time of 0.3s. The examination of SEM indicated that the increment of welding current and electrode pressure leads to increment pitting and corrosion rate.