A. A. Eliseev

Ultrasonic-assisted aging in friction stir welding on Al-Cu-Li-Mg aluminum alloy

Friction stir welding (FSW) on Al-Cu-Li-Mg aluminum alloy V-1469 (AA2195) has been carried out to find out the effect of ultrasonic energy on the microstructural evolution of the welded metal. It was found that ultrasonic-assisted FSW (UAFSW) reduced the recrystallized grain size in the stirring zone (SZ), facilitated strain-induced dissolution of both soluble and insoluble intermetallic precipitates, and enhanced solid solution grain recrystallization and precipitation of coherent metastable phases.

Structure and tensile fracture of 1570C aluminum alloy

Both deformation and fracture tensile studies on orientation dependence of 1570C aluminum alloys samples with respect to rolling direction have been carried out. As revealed, the viscous fracture mechanism is more inherent to the samples with orientation transversal to the rolling direction while samples oriented along the rolling direction revealed quasi-brittle areas on the fracture surfaces. Despite practically the same level of the yield stress there is 10% difference I the ultimate stress.

Effect of friction stir welding parameters on defect formation

Friction stir welding is a perspective method for manufacturing automotive parts, aviation and space technology. One of the major problems is the formation of welding defects and weld around the welding zone. The formation of defect is the main reason failure of the joint. A possible way to obtain defect-free welded joints is the selection of the correct welding parameters. Experimental results describing the effect of friction stir welding process parameters on the defects of welded joints on aluminum alloy AMg5M have been shown. The weld joint defects have been characterized using the non-destructive radioscopic and ultrasound phase array methods. It was shown how the type and size of defects determine the welded joint strength.

Effect of Ultrasonic Application during Friction Stir Welding on Microstructure and Properties of AA2024 Fixed Joints

Microstructure and mechanical properties of aluminum alloy 2024 fixed joint produced by ultrasonic assisted friction stir welding are described. Tensile strength, microhardness, grain size and zone area are measured and compared with ones of joint produced without ultrasonic vibration. Analyzing this data authors make conclusion about ultrasonic vibration effect on friction stir welding joint quality.

Microstructure of Fixed Butt Joints Formed by Friction Stir Welding on 2024T3 Aluminum Alloy

Friction stir welded butt joints on 2024T3 alloy have been obtained using two different process regimes. The microstructures of all the weld joint zones have been examined and such structural parameters as grain size, particle size and volume content of particles have been determined in order to find correlations with the microhardness of the corresponding zones.

Ultrasonic-assisted friction stir welding on V95AT1 (7075) aluminum alloy

Ultrasonic-assisted friction stir butt welding on aluminum alloy V95AT1 (7075) has been carried out. Samples have been characterized using metallography, microhardness and XRD. As shown, ultrasonic treatment during welding provides extra plasticizing of metal and better stirring efficiency. The latter serves for elimination of defects, such as root flaw and grain refining in the stir zone. The stress state in the welded joint is characterized by tensile stress in the direction of the weld seam centerline and compression in the transversal direction. The ultrasonic treatment was shown to increase the compression stress and relieve the tensile one.

Structure and properties of fixed joints formed by ultrasonic-assisted friction-stir welding

This paper deals with structure and properties of aluminum alloy 7475 and its joints obtained by friction stir welding including under ultrasonic action. Microhardness measurements show that ultrasonic action increases strength properties of the joints. Optical and transmission electron microscopy reveals that this effect is related to the precipitation of tertiary coherent S-and T-phase particles.

Towards the problem of forming full strength welded joints on aluminum alloy sheets. Part II: AA7475

The microstructural evolution in welded joint zones obtained both by friction stir welding and ultrasonic– assisted friction stir welding on dispersion hardened 7475 aluminum alloy has been examined together with the analysis of mechanical strength and microhardness. It was established that ultrasonic-assisted friction stir provided leveled microhardness profiles across the weld zones as well as higher joint strength as compared to those of standard friction stir welding.

Mechanical Properties of Additive Manufactured Complex Matrix Three-Component Carbon Fiber Reinforced Composites

Mechanical strength of carbon fiber reinforced composites made of thermoplastic-thermosetting polymer matrix reinforced by carbon fibers has been determined. High mechanical strength has been revealed in tensile and compression tests both along and across the fibers. Specificity of fracturing in fiber-thermoplastics-thermosetting composition has been revealed. The effect of fiber bundling type on fracturing has been addressed.

Tensile strength on friction stir processed AMg5 (5083) aluminum alloy

The results of the tensile tests carried out both on AMg5 (5083) aluminum alloy samples base and those obtained using friction stir processing technique are reported. The tensile test samples have been prepared from the friction stir processed plates so that their tensile axis was parallel to the processing direction. The maximum tensile strength of the processed samples was 9% higher than of the base metal. The fractographic examination shows the presence of flat areas inherent of the brittle fracture in all three friction processed samples. The load-extension curves show that friction stir processing may suppress the serrated yielding.