mechanical qualification of the hybrid metal extrusion bonding hyb process for butt welding of 4 mm plates of aa6082 t6

Abstract Hybrid Metal Extrusion & Bonding (HYB) is a novel solid state joining technique mainly developed for aluminum alloys. By the use of filler material addition and plastic deformation sound joints can be produced at operational temperatures below 400℃. Here, we present the results from an exploratory investigation of the mechanical integrity of a 4 mm AA6082-T6 HYB joint, covering both hardness, tensile and Charpy V-notch testing of different weld zones. The joint is found to be free from defects like pores, internal cavities and kissing-bonds. Still, a soft heat affected zone (HAZ) is present. The joint yield strength is 54 % of the base material, while the corresponding joint efficiency is 66 %. Therefore, there is room for further optimization of the HYB process. This work is now in progress

Electrical and thermal stability of Al-Cu welds: Performance benchmarking of the hybrid metal extrusion and bonding process

Advances in joining processes for aluminum and copper are sought after to facilitate the greater adoption of aluminum in electrical applications. Aluminum's chemical affinity to copper causes the joining and lifetime of Al-Cu welds to be vulnerable to the formation of various intermetallic compounds. Intermetallic compounds and the resulting weld structure are known to reduce the structural integrity and increase the electrical resistance of Al-Cu welds. In this study we evaluate the novel joining process, Hybrid Metal Extrusion and Bonding, for butt welding aluminum and copper. The weld structure was examined using scanning and transmission electron microscopy, and the weld resistance was measured using four-point measurements forecast to the weld interface. Energy dispersive spectroscopy and electron diffraction zone axis patterns were analysed to identify intermetallic compounds. Weld samples were examined pre and post heat treatment at 200 °C, 250 °C and 350 °C for total durations of over 1000 h. The results are compared to existing Al-Cu joining processes, and a new metric, weld interface resistivity, is proposed to compare the electrical properties of bimetallic welds. The Hybrid Metal Extrusion and Bonding process was found to form a thin, consistent and straight intermetallic layer with negligible impact on electrical resistance in the as-welded condition. Artificial ageing of samples by heat treatment established the overall growth rate of intermetallic compounds. The growth rate was used to evaluate the weld's operational lifetime versus temperature. The intermetallic growth rate of Hybrid Metal Extrusion and Bonding was quantified at 200 °C and compared to alternative processes. The Hybrid Metal Extrusion and Bonding process showed a significant performance advantage requiring the longest time to reach 2 μm thickness. Furthermore, the growth of intermetallic compounds did not increase the electrical resistance of the weld interface. The negligible impact on electrical resistance and slow intermetallic growth are promising results of the potential functional performance. This study is the first characterisation of the Hybrid Metal Extrusion and Bonding process for electrical applications showcasing its exciting potential for the joining of aluminum and copper.publishedVersio

Process Modelling Applied to Aluminium-Steel Butt Welding by Hybrid Metal Extrusion and Bonding (HYB)

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Progress in Solid State Joining of Metals and Alloys

In this overview, a new solid-state joining method for metals and alloys is presented, where the best features of gas metal arc welding, friction stir welding and cold pressure welding are combined. The invention, which is known as the Hybrid Metal Extrusion & Bonding (HYB) process, utilizes continuous extrusion as a technique to squeeze the aluminum filler material into the groove between the two plates to be joined under high pressure to achieve metallic bonding. Originally, the idea was to use the HYB process for simple butt joining of aluminum plates and profiles. However, over the years it has evolved into a multi-functional joining process handling a wide range of different joint configurations (butt, fillet and slot welds) and base metal combinations (Al, Fe, Ti and Cu). At present, up to four different metals can be joined together in one pass using the HYB PinPoint extruder and AA6082 as filler wire

Using the Hybrid Metal Extrusion & Bonding (HYB) Process for Butt Welding of 4 mm Plates of AA6082-T6

Hybrid Metal Extrusion & Bonding is a new solid state joining technique developed for aluminium alloys. By the use of filler material addition and plastic deformation sound joints can be produced at operational temperatures below 400 °C. This makes the HYB process more flexible and less vulnerable to defects compared to conventional solid state processes. Here, we present the results form an exploratory investigation of the mechanical integrity of a 4 mm AA6082-T6 HYB joint, covering both hardness, tensile and Charpy V-notch testing of different weld zones. The joint is found to be free from internal defects like pores, cavities and kissing bonds. Still, a soft heat affected zone (HAZ) is present. The joint yield strength is 54 % of the base material, while the corresponding joint efficiency is 66%. Therefore, there is a potential for further optimization of the HYB process. This work is now in progress

Mechanical behavior of gas metal arc AA6082-T6 weldments

A series of experiments have been conducted to determine the mechanical properties of AA6082-T6 plates which have been joined by means of the Gas Metal Arc technique. Hardness Vickers tests, bending tests, tensile tests, fatigue tests and Charpy V-notch tests have been carried out to characterize the joints. In addition, an accurate microstructure analysis of selected fracture surfaces has been done. From the tests it is concluded that HAZ softening brings to a reduction in strength with respect to the parent material. It has been noticed that there is a minimum value of hardness in the heat affected zone, that corresponds to the weakest part of the component. From the Charpy V-notch impact tests it has been observed that the material in the HAZ has the highest energy absorption capacity

Using the Hybrid Metal Extrusion & Bonding (HYB) Process for Butt Welding of 4 mm Plates of AA6082-T6

Hybrid Metal Extrusion & Bonding is a new solid state joining technique developed for aluminium alloys. By the use of filler material addition and plastic deformation sound joints can be produced at operational temperatures below 400 °C. This makes the HYB process more flexible and less vulnerable to defects compared to conventional solid state processes. Here, we present the results form an exploratory investigation of the mechanical integrity of a 4 mm AA6082-T6 HYB joint, covering both hardness, tensile and Charpy V-notch testing of different weld zones. The joint is found to be free from internal defects like pores, cavities and kissing bonds. Still, a soft heat affected zone (HAZ) is present. The joint yield strength is 54 % of the base material, while the corresponding joint efficiency is 66%. Therefore, there is a potential for further optimization of the HYB process. This work is now in progress

On the mechanical integrity of AA6082 3D structures deposited by hybrid metal extrusion & bonding additive manufacturing

Hybrid Metal Extrusion and Bonding Additive Manufacturing (HYB-AM) is a new solid-state process for the production of 3D metal structures. In HYB-AM, the wire feedstock is continuously processed through an extruder and deposited in a stringer-by-stringer manner to form layers and eventually a near net-shape component. In this work, the layer bonding of AA6082 samples produced by this process has been investigated by means of tensile testing, hardness measurements and microscope analyses. Furthermore, a novel method for the fabrication of miniature tensile specimens for assessing the bond strength across the layers is presented and applied. The test results reveal that the ultimate tensile strength is approaching that of the substrate material of the same alloy, yet with a somewhat lower elongation prior to fracture. Microscope analyses show that the bonded interfaces are fully dense; however, the fracture surfaces reveal regions of kissing-bonds and lack of bonding. Still, these preliminary investigations indicate that the HYB-AM process, upon further optimization, has the potential of processing high quality aluminum alloy components

Fatigue properties of AA6060-T6 butt welds made by hybrid metal extrusion & bonding

The present investigation is concerned with high‐cycle axial fatigue testing of a 2‐mm AA6060‐T6 hybrid metal extrusion & bonding (HYB) butt weld produced in the solid state using AA6082 filler metal addition. The results complement the three‐point bend testing and the tensile testing done in two previous studies. In this study, optical microscope and scanning electron microscope examinations have been carried out to reveal the joint macro/microstructure and document possible surface and root defects deemed to affect fatigue life. In the as‐welded condition, the HYB weld suffers from surface irregularities at the weld face and ‘kissing’ bond formation in the root region. Despite of this, the subsequent testing shows that the fatigue properties exceed those reported for comparable AA6082‐T6 gas metal arc butt welds and matching those reported for corresponding high‐strength laser beam and friction stir weldments