Showing papers in "Science and Technology of Welding and Joining in 2022"
TL;DR: In this article , the authors focus on friction stir additive manufacturing (FSAM) and additive friction stir deposition (AFSD) and provide a system approach framework and a conceptual process model to guide researchers.
Abstract: Additive manufacturing (AM) has completely altered the traditional component manufacturing and qualification paradigm. It provides unitisation and topological optimisation opportunities simultaneously. Broadly, the additive manufacturing processes are classified as fusion-based or solid-state. The solid-state additive manufacturing processes are relatively nascent. Among these, friction stir-based processes involve intense shear deformation of material while building. In this review, we focus on friction stir additive manufacturing (FSAM) and additive friction stir deposition (AFSD). These friction stir welding derived techniques have ability to produce microstructures that lead to better mechanical properties than the conventionally processed parent alloys; in many cases overcoming the traditional strength-ductility tradeoff paradigm. The best way to capture this advantage is to conduct materials selection for build which benefit from the attributes of these processes. This review provides a systems approach framework and a conceptual process model to guide researchers. A case is built that the best mechanical properties can be obtained by alloy design for such disruptive and innovative manufacturing processes. The intrinsic and extrinsic limitations are highlighted to guide researchers in the field of FSAM and AFSD. While AFSD is readily applicable to lower melting temperature materials currently, applying it to high-temperature materials requires significant research and development on tool materials. Examples of materials processed by FSAM/AFSD include aluminium alloys, magnesium alloys, titanium alloys, steels and nickel-base superalloy. A physics-based process modelling framework applicable to FSAM/AFSD is provided. To fully validate such models, it is imperative to use machines with appropriate sensors that capture the machine parameters, tool health, and workpiece temperature.
29 citations
TL;DR: In this paper , high-speed friction stir welding (HSFSW) joints are produced by adopting aggressive material mixing, i.e., higher tool rotation and plunge force. But, the defect-free HSFSW joints are not produced by using the same material mixing as in this paper.
Abstract: Present work aims to achieve high welding speed during friction stir welding of lightweight battery trays in the electric vehicle industry. This study reports high-speed friction stir welding (HSFSW) up to 4.0 m min−1 in AA6063-T6 alloys. The defect-free HSFSW joints are produced by adopting aggressive material mixing, i.e. higher tool rotation and plunge force. HSFSW weld cross-section reported an unusual hardness profile of ‘U’ shape instead of ‘W’ shape in conventional FSW of AA6xxx alloys. HSFSW resulted softening of weld stir zone (∼60HV) along with HAZ (∼53HV) against the base material (BM) hardness of ∼90HV. The HSFSW at 4.0 m min−1 obtained good joint strength of 71% of the BM. Microstructure evolutions across the fractured weld cross-section are discussed using EBSD analysis.
16 citations
TL;DR: In this article, the authors investigated the effect of adding Titanium diboride (TiB2) nucleant particle addition to the high strength Aluminium 2319 alloy produced during wire arc additive manufacturing (WAAM).
Abstract: Controlling the grain size and morphology during fusion-based additive manufacturing remains a challenge for many alloys. This work investigates Titanium diboride (TiB2) nucleant particle addition to the high strength Aluminium 2319 alloy produced during wire arc additive manufacturing (WAAM). Two Cold Metal Transfer (CMT) processing conditions are explored (low heat input CMT and high heat input CMT) and the effectiveness of the grain refiner is studied. The addition of TiB2 is found to refine the average equiaxed grain size by up to 22% compared to the non-inoculated alloy. The Interdependence Model is applied to understand the grain refinement mechanisms occurring in low heat input AM technologies in alloys containing powerful growth restricting solutes such as Al 2319.
9 citations
Abstract: The effect of cooling rate on the solidification behaviour of austenitic stainless steels during high energy density welding and directed energy deposition (DED) has been reviewed. Precedent studies demonstrated the confinement of austenite–ferrite duplex region and the susceptibility of specific alloy compositions on the Schaeffler diagram to alteration of solidification mode at high cooling rates during the high energy density welding. Meanwhile, mitigated cooling conditions have dominated during the DED process. The instances of microstructural fluctuations owing to cooling rate variation have been compiled. The incorporation of DED steels into the implicated Schaeffler diagrams demonstrated reliable predictions at high cooling rates. The printability of austenitic stainless steels during the DED process has been discussed in terms of solidification cracking susceptibility.
9 citations
TL;DR: In this article , the three-dimensional interfacial morphology and property of eutectic SnPb solder joint under an extreme thermal shocking of 77 −423 K were investigated to meet the demand of cryogenic reliability on the electronic packaging for deep space satellite, and the results showed that the shear force of solder joint was greatly reduced due to broken Cu6Sn5 with the changing fracture characteristics from the solder controlled mode to the solder/IMC mixed mode.
Abstract: To meet the demand of cryogenic reliability on the electronic packaging for deep space satellite, the three-dimensional interfacial morphology and property of eutectic SnPb solder joint under an extreme thermal shocking of 77–423 K were investigated. After thermal shocking, Cu-Sn IMC layers coarsened in the cross-sectional observation and micro-cracks formed in Cu6Sn5 layer. The rough Cu6Sn5 layer in the top view gradually smoothed, with broken Cu6Sn5 particles and exposed Cu3Sn. In the bottom-view observation, the Cu6Sn5 layer of as-soldered joint was overlapped by Cu3Sn layer. But no defects were generated in Cu3Sn layer. The shear force of solder joint was greatly reduced due to broken Cu6Sn5 with the changing fracture characteristics from the solder-controlled mode to the solder/IMC mixed mode.
9 citations
TL;DR: In this paper , a shipbuilding steel has been submerged arc welded under 6 kJ mm−1 heat input employing CaF2-TiO2 fluxes, and the inclusion size distribution curves show log-normal patterns with the frequency peaks ranging from 0.3 to 0.4 μm.
Abstract: EH36 shipbuilding steel has been submerged arc welded under 6 kJ mm−1 heat input employing CaF2–TiO2 fluxes. Ensuing weld metals have been examined with an emphasis on inclusion characteristics. Compositional-wise, the inclusion ensemble is largely categorised as a complex Ti-containing type. It is demonstrated that, as a function of TiO2 content, the average Ti content in the inclusions is gradually enhanced, which is compensated by the simultaneous reduction of Al and Mn. Meanwhile, inclusion size distribution curves show log-normal patterns with the frequency peaks ranging from 0.3 to 0.4 μm. Furthermore, inclusion number density and volume fraction show a definitive increasing trend, which are concurrent to the O uptake from 110 to 210 ppm enabled by TiO2 decomposition.
8 citations
TL;DR: In this paper , the relative percentage of acicular ferrites decreases from 62.2 to 41.3%, while that of grain boundary ferrites increases from 10.4 to 30.2%, which are enabled by the diminished number of potent nuclei at lower cooling rate and largely responsible for the reduced hardness and toughness.
Abstract: Microstructure evolution roadmap and pertinent mechanical responses in weld metals subjected to various heat inputs have been profiled in EH420 shipbuilding steel by scanning electron microscopy, energy dispersive spectrometry, electron backscatter diffraction and mechanical testing. As the heat input increases from 11.5 to 20 kJ mm–1, relative percentage of acicular ferrites decreases from 62.2 to 41.3%, while that of grain boundary ferrites increases from 10.4 to 30.2%, which are enabled by the diminished number of potent nuclei at lower cooling rate, and largely responsible for the reduced hardness and toughness.
8 citations
TL;DR: In this paper , the intermetallic compounds (IMCs) layers formed at Al/Mg interface in welds were characterised by TEM, and the IMCs were generated by solid-state atomic diffusion in butt joints under the used welding conditions since the measured temperature at the tool/workpiece interface was far below the eutectic points.
Abstract: Frictions stir welding (FSW) and ultrasonic vibration enhanced FSW (UVeFSW) of dissimilar Al/Mg alloys were conducted, and the intermetallic compounds (IMCs) layers formed at Al/Mg interface in welds were characterised by TEM. It was found that the IMCs thickness was significantly reduced in UVeFSW, and the IMCs were generated by solid-state atomic diffusion in butt joints under the used welding conditions since the measured temperature at the tool/workpiece interface was far below the eutectic points. The EBSD characterisation showed that ultrasonic vibration improved the degree of grain recrystallization on both sides of the IMCs layers and promoted the consumption of dislocations, which resulted in a reduced diffusion rate of atoms. Therefore, the growth of IMC layer was suppressed in UVeFSW.
7 citations
TL;DR: In this paper , the asymmetric weld fusion geometry in oscillating laser beam welding (OLBW) of aluminium alloy was investigated using a numerical approach using a multi-physics heat transfer and fluid flow model of OLBW.
Abstract: In this work, the asymmetric weld fusion geometry in oscillating laser beam welding (OLBW) of aluminium alloy was reported and investigated using a numerical approach. A multi-physics heat transfer and fluid flow model of OLBW was developed and validated with the corresponding experimental results. The weld fusion geometry, temperature fields, and fluid flow behaviours for four commonly used oscillation modes, line, circle, eight, and infinity, were calculated to analyse the origin of the asymmetric weld fusion geometry. The results show the asymmetry of local heat input along beam travelling path and the fluid flow pattern in the molten pool are the main factors that result in the asymmetric weld fusion geometry in OLBW.
6 citations
TL;DR: In this article , the effect of Zn interlayer on the microstructure and mechanical properties of dissimilar A1100 and SUS316L friction stir welded (FSW) butt joints was investigated.
Abstract: The effect of Zn interlayer on the microstructure and mechanical properties of dissimilar A1100 and SUS316L friction stir welded (FSW) butt joints was investigated. The results showed that Zn could improve the joint’s tensile strength. However, a complete dissolution of the Zn interlayer was necessary to achieve a sound joint. During the FSW process, the stirring action of the tool dispersed the Zn into the A1100 matrix forming a solid solution of Zn. A direct relationship was found between the tool rotational speed and the Zn dissolution rate. Also, the addition of Zn inhibited the Al–Fe IMCs growth, which played a positive role in the obtained tensile strength.
6 citations
TL;DR: In this article , a face centred cubic (FCC) structure was observed in both base metal and laser-welded conditions in CoCrFeNi and CoCrCuFeNi HEA was carried out.
Abstract: In this work, laser welding of CoCrFeNi and CoCrCuFeNi HEA was carried out. X-ray diffraction, electron backscattered diffraction, mechanical property and microstructural analyses were performed. In CoCrFeNi alloy, a face centred cubic (FCC) structure was observed in both base metal and laser-welded conditions. The addition of Cu in CoCrFeNi alloy is resulted in two FCC phases and has increased the tensile strength from 593 to 666 MPa. The fusion zone of both the welds shows coarser columnar grain and lower hardness compared to that of base metals. Post-welding results show 53% decrease in tensile strength in the alloy containing Cu (CoCrFeNiCu). Whereas only a marginal decrease in strength is observed in CoCrFeNi alloy.
TL;DR: In this paper , the effect of preheating temperature on the interfacial connection of Ni-based coatings was investigated, and it was shown that metallurgical bonding can be achieved between coating and copper substrate only when the preheat reached at least 500°C.
Abstract: To further clarify the characteristics of plasma cladding on copper surface, the effect mechanism of preheating temperature on the interfacial connection of Ni-based coatings was investigated. Results showed that metallurgical bonding can be achieved between coating and copper substrate only when the preheating temperature reached at least 500°C. Without preheating, the heat of the plasma arc was conducted away by the copper with high thermal conductivity, making it difficult to form a molten pool. At low temperatures (300°C and 400°C), the copper oxides formed on copper surface during preheating had poor wettability with the liquid Ni-based alloy, resulting in unreliable interfacial connection. Properly increasing (above 500°C) the preheating temperature can promote the removal of copper oxides, thereby improving the interfacial wettability. Moreover, to avoid performance degradation caused by excessive dilution ratio, controlling the preheating temperature at about 600°C is more appropriate.
TL;DR: In this paper , cold spray and laser powder bed fusion was explored and found to significantly increase the peak force and fracture energy of the press hardened boron steel-aluminium joint.
Abstract: ABSTRACT Cold spray and laser powder bed fusion deposition processes were explored and found to significantly increase the peak force and fracture energy of the press hardened boron steel–aluminium joint. The use of 250 µm thick 316L metallic interlayers was resistance spot welded to an AlSi-coated press hardened steel and 6022-T4 aluminium alloy. Moreover, aluminium penetration within the deposited 316L promoted a mechanical locking effect which was assessed by increasing the hatch spacing in the laser powder bed fusion process from 100 to 200 µm.
TL;DR: In this article , double side friction stir welding (DS-FSW) was used to join TC4 titanium alloy and 2024-T4 aluminium alloy having dissimilar medium-thick plates with a thickness of 8 mm.
Abstract: Double side friction stir welding (DS-FSW) was used to join TC4 titanium alloy and 2024-T4 aluminium alloy having dissimilar medium-thick plates with a thickness of 8 mm. The microstructure and mechanical properties in medium-thick Ti/Al dissimilar DS-FSW joints were systematically studied. It revealed that the diffusion-type Ti/Al interface was mainly formed when the rotating speed is low. While intermetallic compounds layers were formed at the Ti/Al interface due to the high welding temperature and intense mechanical mixing at a relatively high rotating speed. The maximum tensile strength of medium-thick Ti/Al dissimilar DS-FSW joint is 265 MPa achieved at the rotation speed of 300 rev min–1, which is 58.9% of the base material of 2024-T4 aluminium alloy.
TL;DR: In this paper , a computer tomography technique was employed to obtain the three-dimensional information of material flow around the tool, and the top view of copper powders distribution inside the weldments showed that the distribution zones of marker material at the retreating side and the trailing side were all widened by the exerted ultrasonic vibration.
Abstract: Comparative experiments of friction stir welding (FSW) of Al/Mg alloys were conducted with and without ultrasonic assistance. The copper powders were preset inside the workpieces as the marker material, and computer tomography technique was employed to obtain the three-dimensional information of material flow around the tool. The top view of copper powders distribution inside the weldments shows that the distribution zones of marker material at the retreating side and the trailing side were all widened by the exerted ultrasonic vibration (UV). The front view and side view of marker material distribution demonstrated that UV also enhanced the vertical material flow. Such detection results are helpful to elucidate the mechanism of ultrasonic-assisted FSW of dissimilar Al/Mg alloys.
TL;DR: In this paper , a semi-empirical model for peak temperature estimation during FSW of aluminium alloys was proposed, and a threshold peak temperature was defined to avoid cold defects by combining temperature measurements with joint quality information obtained from X-ray scans.
Abstract: Process parameters and base material thermal properties strongly affect peak temperature evolution in friction stir welding (FSW). This work develops a semi-empirical model for peak temperature estimation during FSW of aluminium alloys. Several bead-on-plate runs were conducted on AA5083-H111, AA6082-T6 and AA7075-T6. Different rotational and welding speeds were tested while measuring the temperature with a thermocouple embedded in the tool. A polynomial model was proposed with the model's coefficients strongly correlating to the material thermal properties. Additionally, a threshold peak temperature was defined to avoid cold defects by combining temperature measurements with joint quality information obtained from X-ray scans. The efficiency of the model and the defined threshold are proven by applying them to the literature.
TL;DR: In this paper , more than 63,766 dynamic resistance curves of welding points were collected in manufacturing sites, and the machine learning method was applied to monitor the resistance spot welding expulsion.
Abstract: There is still a lack of effective monitoring methods for resistance spot welding expulsion in manufacturing sites. In this study, more than 63,766 dynamic resistance curves of welding points were collected in manufacturing sites, and the machine learning method is applied to monitor the resistance spot welding expulsion. Generally, the model’s generalisation ability is poor due to the complex conditions of the manufacturing site. This study solves this problem by improving the data preprocessing and model selection method. The experimental results show that when the process parameters do not change, the accuracy of expulsion recognition can easily reach 95%. When the process parameters change, it can reach 90% by selecting the appropriate data preprocessing method and model selection.
TL;DR: In this article , the effects of welding hold time on weld quality of aluminium alloy to dual-phase steel resistance spot welds were studied, and it was shown that there existed an optimum range of hold time (350∼500 ms), within which the largest weld nugget diameter (7.6 mm), thinnest intermetallic compound (IMC) layer (1∼5µm) and maximum tensile shear peak load (4.7 kN) were obtained.
Abstract: The effects of welding hold time on weld quality of aluminium alloy to dual-phase steel resistance spot welds were studied. Results demonstrated that there existed an optimum range of hold time (350∼500 ms), within which the largest weld nugget diameter (7.6 mm), thinnest intermetallic compound (IMC) layer (1∼5 µm) and maximum tensile shear peak load (4.7 kN) were obtained. Too short hold time led to shrinkage, small weld nugget and thick IMC layer due to reduced heat dissipation after removing electrodes, thus resulting in low tensile peak load and brittle fracture along the IMC layer. While too long hold time, i.e. 750 ms, produced a smaller weld nugget diameter due to more rapid heat dissipation.
TL;DR: In this paper , the first derivative of the dividing line at the boundary of SZ was extracted to investigate material flow, and the material experienced different viscous slips when rotating around the pin, which disengaged pin at larger slip and adhered to pin at a smaller slip.
Abstract: The flow and slip rate of material in friction stir welding mainly determined the weld quality, flow rate depended not only on the shape of pin and welding parameters but also on slip, and an instantaneous centre of speed was generated by rotating speed and welding speed. The relative speed of contact interface is generally an important factor in material flow. The material experienced different viscous slips when rotating around the pin, which disengaged pin at a larger slip and adhered to pin at a smaller slip, resulting in large differences in two sides. The first derivative of the dividing line at the boundary of SZ was extracted to investigate material flow.
TL;DR: In this article , a real-time simultaneous monitoring of the arc current, voltage and power, and the nature of surface temperature field and filler wire deposition during the process is presented.
Abstract: Gas metal arc-directed energy deposition is a metal additive manufacturing technique that involves the melting of a filler wire under an electric arc resulting in a high rate of deposition of molten metal and fast building of large scale parts in a layer-by-layer manner. A novel attempt is presented here for real-time simultaneous monitoring of the arc current, voltage and power, and the nature of surface temperature field and filler wire deposition during the process. The recorded temperature fields are analysed to trace the layer-wise variation in melt pool dimensions and solidification cooling rates. Together these process signatures demonstrated a synchronised assessment and potential to support an integrated feedback control system for gas metal arc-directed energy deposition.
TL;DR: In this article , the transverse motion weldability (TMW) test was applied to the 2000-, 6000- and 7000-series Al alloys but not the 5000-series.
Abstract: The recently developed transverse-motion weldability (TMW) test, in which a motor pushes the lower sheet in lap welding at velocity V to induce solidification cracking, has been applied to the 2000-, 6000- and 7000-series Al alloys but not the 5000-series. Here, alloy 5052 was TMW-tested under essentially identical conditions including the motor torque that caused the pushing force on the lower sheet. Surprisingly, the fracture surface of the fusion zone was flat instead of dendritic as expected from solidification cracking. When the torque was set at lower levels, a higher V was required to cause cracking, but the fracture surface became dendritic. The torque effect on cracking in alloy 5052 was discussed, and alloy 2219 was also tested for comparison.
TL;DR: In this paper , a low heat-input double-pulse gas metal arc welding (LHDP-GMAW) was proposed based on doublepulse GMAW for low-melting-point metal welding.
Abstract: Double-pulse gas metal arc welding (DP-GMAW) is a common low-melting-point metal welding method. In this study, a low heat-input double-pulse gas metal arc welding (LHDP-GMAW) was proposed based on DP-GMAW. The welding process stability, weld bead shape, microstructure, and microhardness of 6061 aluminium alloy welding were analyzed for DP-GMAW and LHDP-GMAW with different low-frequency (3, 5 and 7 Hz). Compared with DP-GMAW, the stirring effect of alternating strong and weak pulses on the molten pool of LHDP-GMAW is enhanced and the heat input is reduced. Therefore, the LHDP-GMAW can produce more obvious fish-scale ripples, lower penetration, smaller and more uniform grains, and higher microhardness. This study provides a new solution for improving the welding quality of low-melting-point metal.
TL;DR: In this paper , the mechanical properties of steel and AA5182 aluminium alloy in triple combinations joined by the self-piercing riveting (SPR) method were investigated.
Abstract: Self-piercing riveting (SPR) is a high-speed mechanical joining technique for sheet metal materials. In this study, the mechanical properties of DC04 steel and AA5182 aluminium alloy in triple combinations joined by the SPR method were investigated. For this purpose, triple-joining processes were performed in different combinations, and macro-structural analysis and tensile shear tests were carried out by comparing their mechanical properties. As a result of the study, the highest shear forces were obtained in FFA (DC04-DC04-AA5182) and AFF (AA5182-DC04-DC04) combinations. As the number of aluminium layers increases, the probability of tearing increases in triple joining. Higher spread ratios were generally measured under conditions with hard materials in the upper layers and soft materials in the lower layers.
TL;DR: In this paper , the liquation cracking temperature range (LCTR) of CM247LC was evaluated, especially in remelted and reheated weld metals produced during multi-pass repair welding.
Abstract: The liquation cracking temperature range (LCTR) of CM247LC was evaluated, especially in remelted and reheated weld metals produced during multi-pass repair welding. The LCTR of the remelted weld metal was 282 K, and those of the reheated weld metals were 455–805 K depending on the testing position. In the multi-bead within the reheated weld metal, the LCTR increased from 455 K far from the inter-pass boundary to 805 K near this boundary. The mechanism underlying the varying LCTR for the remelted and reheated weld metals was the amount of MC carbide at each weld position. The single-mode fibre laser welding suppressed the carbide within both areas, and lowered the liquation cracking susceptibility.
TL;DR: In this article , the influence of additives and welding speed on tensile strength and characterisation across the welding interface was studied, where Al-CNT additives were placed in a gap between the AZ61 and steel specimens.
Abstract: The friction stir alloying (FSA) procedure successfully produced dissimilar joints between AZ61 magnesium alloy and mild steel with Al-CNT additions. Before welding, Al-CNT additives were placed in a gap between the AZ61 and steel specimens. The experimentation was performed using different welding speeds while tool rotational speed was kept constant for varying weight percentages of carbon nanotubes (CNT) in Al powder. The influence of additives and welding speed on tensile strength and characterisation across the welding interface was studied. Tensile strength of joint with 3% CNT improved up to 222 MPa. Al-rich intermetallic compounds were found at the welding contact, while the formation of Al2MgC2 carbide was detected, which contributed to CNT strengthening effects all to improved welding strength.
TL;DR: In this paper , the interfacial texture and bonding strength of Cu/Al laminate metal composite fabricated by ultrasonic additive manufacturing (UAM) were investigated by electron backscattered diffraction, transmission electron microscopy and peeling tests.
Abstract: Interfacial texture and bonding strength of Cu/Al laminate metal composite fabricated by ultrasonic additive manufacturing (UAM) were investigated by electron backscattered diffraction, transmission electron microscopy and peeling tests. Results show that after the UAM process, Al foils have obvious shear texture or recrystallisation texture components in the region near the interface of Cu/Al, indicating that Al foils are prone to shear deformation during consolidation, which plays an essential role in the bonding formation of the two dissimilar metals. The rougher Cu foil surface produced by direct contact with sonotrode promotes more remarkable shear deformation of the mating Al foil near the interface during the subsequent consolidation pass, which obviously enhances the interfacial bonding strength.
TL;DR: In this paper , the microstructure, inclusions and cryogenic impact toughness of Fe-22.03Mn-0.45C austenitic weld metal were investigated.
Abstract: Microstructure, inclusions and cryogenic impact toughness of Fe-22.03Mn-0.45C austenitic weld metal were investigated. The results show that microstructure of weld metal consisted of straight columnar dendrites with different orientations. Microsegregation of Mn was observed in the interdendritic regions and Mn depletion thus occurred in the dendrite core, which is suggested to lead to the different morphologies of MnS oxides (Mn–Al–Si–O) depending on their location. MnS patch-type oxides were found at dendrite boundary and MnS shell-type oxides were found at dendrite core. Inclusions as crack sources were distributed in the dimple of cryogenic impact fractography, it was found that MnS patch-type oxides were more ready to act as a crack source and cause the formation of dimples than MnS shell-type oxides.
TL;DR: In this paper , a numerical approach was proposed to predict the failure of resistance spot welds, into which theoretical and empirical models as well as finite element (FE) model are integrated.
Abstract: In this study, a numerical approach was proposed to predict the failure of resistance spot welds, into which theoretical and empirical models as well as finite element (FE) model are integrated. In this approach, the hardness of spot welds was first evaluated and the estimated hardness was then used to determine the local mechanical properties. The weld geometry and boundary conditions were faithfully followed when generating the FE model. A Gurson-type damage model and a cohesive zone model were simultaneously considered for the two main failure modes, i.e. pull-out failure and interface failure. The predictions were validated by experimental observations. The successful estimation of critical nugget size, as an exemplary application, demonstrated the utility and reliability of this approach.
TL;DR: In this paper , a good metallurgical bond was formed between silica glass and 2024 aluminium alloy with the assistance of ultrasonic wave, and the effects of different experimental parameters on the properties and morphology of soldering joints were discussed.
Abstract: Sn–9Zn–2Al solder alloy was used to weld silica glass and 2024 aluminium alloy with the assistance of ultrasonic wave. It can be concluded from the results that a good metallurgical bond can be formed between silica glass and 2024 aluminium alloy. The effects of different experimental parameters on the properties and morphology of soldering joints were discussed. In the use of ultrasound assisted conditions, the Al–Zn–Sn solution layer was generated on the side of the Sn–Zn–Al solder alloy and 2024 aluminium alloy due to atomic diffusion. In addition, there was an oxide layer between the solid solution layer and the solder alloy. The reason is that Al atoms can combine with O atoms under the action of ultrasonic wave, and the deposition reaction occurs to form an alumina layer. Finally, the interface structure of the soldering joint is silica glass/Sn–Zn eutectic phase, α-Al phase, β-Zn phase/Al2O3 oxide layer/Al–Zn–Sn solution layer/2024 aluminium alloy.
TL;DR: In this article , a novel Fe/Cu interface with excellent mechanical properties in a magnetic yoke was fabricated by friction stir welding, which eliminated defects that commonly form during conventional bead welding.
Abstract: A novel Fe/Cu interface with excellent mechanical properties in a magnetic yoke was fabricated by friction stir welding. This method eliminated defects that commonly form during conventional bead welding. The thick oxidisation layer at the Cu/Fe surface that formed due to fusion welding was eliminated during friction stir welding (FSW). Combined with the severe deformation introduced by FSW, the Cu/Fe interface obtained by fusion welding was hardly distinguishable due to mutual embedding at the Cu/Fe interface. The in situ digital image correlation analysis indicated that this Cu/Fe interface reconstruction also modified the deformation and crack propagation behaviours. The tensile load and displacement of the joint by FSW were remarkably improved while maintaining magnetic isolation.