Some studies on mechanical properties of friction stir butt welded Al-6082-T6 plates
The conventional fusion welding of cast aluminium alloys is generally difficult due to some common defects such as porosity, oxide inclusion, and hot cracking, which in turn reduce the weld strength. In recent years, friction stir welding (FSW) was found to be very effective for the welding of various wrought aluminum alloys. This paper investigates a metal joining process called Friction Stir Welding (FSW), an innovative welding technique invented by TWI Ltd. in Great Britain in 1991. The purpose of the paper is to study the effects of process parameters in the butt welding of Al-6082-T6 plates with a thickness of 3 mm. Joints were made using different combinations of tool rotation speed, welding speed, and axial force, each at different levels. The quality of weld zone was analyzed using macrostructure. The study aims in identifying the process parameters of welding the Al6082 alloy and the effect of welding speed on the weld performance of the joint was investigated by conducting tensile and hardness tests.
Effect of process parameters on the strength of resistance spot welds in 6082-T6 aluminium alloy
In this study the microstructural and mechanical behaviour of resistance spot welds (RSW) done on aluminium alloy 6082-T6 sheets, welded at different welding parameters, is examined. Microstructural examinations and hardness evaluations were carried out in order to determine the influence of welding parameters on the quality of the welds. The welded joints were subjected to static tensile-shear tests in order to determine their strength and failure mode. The increase in weld current and duration increased the nugget size and the weld strength. Beyond a critical nugget diameter the failure mode changed from interfacial to pullout. Taking into consideration the sheet thickness and the mechanical properties of the weld, a simple model is proposed to predict the critical nugget diameter required to produce pull-out failure mode in undermatched welds in heat-treatable aluminium alloys.
SMC composites waste management as reinforcing fillers in polypropylene by combination of mechanical and chemical recycling processes
A new process of management of waste of composite materials from Sheet Moulding Compounds (SMC), as reinforcing fillers for thermoplastic materials, including both mechanical and chemical processes is proposed in this paper. Communited SMC being composed of coated glass fibres intimately mixed with calcium carbonate powder, their reinforcing power is low. First, the fibrous part was increased by partial dissolution of calcium carbonate present in the crushed products SMC. Second, a process of partial solvolysis was developed aiming at strong increasing the interfacial mechanical properties by functionalising of SMC load incorporated into polypropylene/grafted maleic anhydride polypropylene (PP/PPgma). At this effect, we investigated a treatment with a hot triamine (diethylenetriamine, DETA) in order to create a functionalisation, after scission of the bond ester of unsaturated polyester, as bridging amino-succinimide.The effect of this recycling way by partial solvolysis was checked from the mechanical properties of the resulting reinforced PP/PPgma material: Although a lower of Young modulus, better yield stress and especially resilience were observed.