Pub Date : 2025-06-01Epub Date: 2025-04-28DOI: 10.1016/j.jajp.2025.100305
M Chelladurai Asirvatham , Iain Masters , Geoff West , Paul Haney
Laser welding of aluminium tabs to nickel-plated interstitial-free (IF) steel was investigated using a high-brightness, single-mode laser with beam wobbling. The influence of interaction time, controlled by wobble amplitude and traverse speed, regulating energy distribution on weld microstructure and mechanical properties was systematically studied. Short interaction times (<25 µs) and large inter-wobble distances (>150 µm) minimized intermetallic compound (IMC) formation and maximized weld strength. Optimizing these parameters (wider wobble amplitudes of 0.6–0.8 mm and faster speeds of 75–100 mm/s) suppressed IMC-induced cracking, resulting in microstructures containing Fe-rich IMCs and Al-Fe₄Al₁₃ eutectic phases. Conversely, lower wobble amplitudes (<0.6 mm) and slower speeds (50–75 mm/s) promoted crack-prone Al-rich Fe₂Al₅ phases. Optimized welds exhibited excellent fatigue performance, withstanding 1 million cycles at 175 N, demonstrating the potential for using lighter, cost-effective aluminium busbars in battery interconnect applications.
{"title":"High-brightness laser welding with beam wobbling: Achieving high-strength Al/Steel joints for battery busbars","authors":"M Chelladurai Asirvatham , Iain Masters , Geoff West , Paul Haney","doi":"10.1016/j.jajp.2025.100305","DOIUrl":"10.1016/j.jajp.2025.100305","url":null,"abstract":"<div><div>Laser welding of aluminium tabs to nickel-plated interstitial-free (IF) steel was investigated using a high-brightness, single-mode laser with beam wobbling. The influence of interaction time, controlled by wobble amplitude and traverse speed, regulating energy distribution on weld microstructure and mechanical properties was systematically studied. Short interaction times (<25 µs) and large inter-wobble distances (>150 µm) minimized intermetallic compound (IMC) formation and maximized weld strength. Optimizing these parameters (wider wobble amplitudes of 0.6–0.8 mm and faster speeds of 75–100 mm/s) suppressed IMC-induced cracking, resulting in microstructures containing Fe-rich IMCs and Al-Fe₄Al₁₃ eutectic phases. Conversely, lower wobble amplitudes (<0.6 mm) and slower speeds (50–75 mm/s) promoted crack-prone Al-rich Fe₂Al₅ phases. Optimized welds exhibited excellent fatigue performance, withstanding 1 million cycles at 175 N, demonstrating the potential for using lighter, cost-effective aluminium busbars in battery interconnect applications.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100305"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-05-28DOI: 10.1016/j.jajp.2025.100317
Tamil Prabakaran S , Sudha J , Siva S , Balamurali Duraivel , Vivekananda A S
Thermite Heat-Assisted Friction Stir Welding (THAFSW) is recognized as an efficient welding method for joining aluminium bronze (AB) alloys. The mechanical and metallurgical characteristics of the welded joints were analyzed and compared with those fabricated using the conventional friction stir welding (CFSW) technique. Tensile strength and hardness assessments of the welded specimens were conducted at ambient temperature. The findings revealed that the THAFSW joints exhibited superior mechanical properties, with tensile strength and elongation improving by 11 % and 25 %, respectively, compared to joints produced through the conventional approach. The strengthening mechanism of the welded joints was examined based on images captured through macroscopy, optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The THAFSW process effectively eliminated tunnel defects and facilitated the development of a uniform α-phase microstructure, which contributed to enhanced mechanical performance.
{"title":"Enhancement of mechanical properties of thermite heat assisted friction stir welded aluminium bronze alloy (C95300) by eliminating tunnel defect","authors":"Tamil Prabakaran S , Sudha J , Siva S , Balamurali Duraivel , Vivekananda A S","doi":"10.1016/j.jajp.2025.100317","DOIUrl":"10.1016/j.jajp.2025.100317","url":null,"abstract":"<div><div>Thermite Heat-Assisted Friction Stir Welding (THAFSW) is recognized as an efficient welding method for joining aluminium bronze (AB) alloys. The mechanical and metallurgical characteristics of the welded joints were analyzed and compared with those fabricated using the conventional friction stir welding (CFSW) technique. Tensile strength and hardness assessments of the welded specimens were conducted at ambient temperature. The findings revealed that the THAFSW joints exhibited superior mechanical properties, with tensile strength and elongation improving by 11 % and 25 %, respectively, compared to joints produced through the conventional approach. The strengthening mechanism of the welded joints was examined based on images captured through macroscopy, optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The THAFSW process effectively eliminated tunnel defects and facilitated the development of a uniform α-phase microstructure, which contributed to enhanced mechanical performance.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100317"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-05-19DOI: 10.1016/j.jajp.2025.100314
Ákos Meilinger, Gábor Terdik
The use of high-strength steels as a substrate for hardfacing is becoming increasingly common in the industry (e.g., for demolition shears). In the case of joint welding, the weldability of these steels is limited because welding heat has significant affect to the base material. Both softening and hardening can occur in the different sub-zones of heat-affected zone, leading to changes in impact properties. For demolition shears, impact stresses are the most critical loads. Heat input can alter the microstructure of the heat-affected zone, potentially reducing the load-bearing capacity due to the penetration depth of the hardface layer or the buffer layer. Robotization of hardfacing creates equal layers with high precision, which helps the precise comparison. In this study, S690QL and S960QL substrates were investigated under different heat inputs, and the impact properties of these specimens were tested. Instrumented impact test results were analyzed and supplemented with surface fractography. The impact resistance of the S690QL substrate decreases with higher heat input and penetration depth. In contrast, S960QL exhibits different behavior: the use of lowest heat input causes a 226 % increase in impact energy compared with the base material. The underlying reasons for this were identified through force-time curve analysis, where the positive effect of the heat-affected zone is determined. Additionally, the maximum impact forces display different behavior for the two materials: S960QL shows higher impact force except in case of highest heat input, where the S690QL shows better force. These findings are valuable for selecting the appropriate substrate and hardfacing technology for this application and its specific loading conditions.
{"title":"Robotized hardfacing on high-strength steels: determination of impact properties with different heat inputs","authors":"Ákos Meilinger, Gábor Terdik","doi":"10.1016/j.jajp.2025.100314","DOIUrl":"10.1016/j.jajp.2025.100314","url":null,"abstract":"<div><div>The use of high-strength steels as a substrate for hardfacing is becoming increasingly common in the industry (e.g., for demolition shears). In the case of joint welding, the weldability of these steels is limited because welding heat has significant affect to the base material. Both softening and hardening can occur in the different sub-zones of heat-affected zone, leading to changes in impact properties. For demolition shears, impact stresses are the most critical loads. Heat input can alter the microstructure of the heat-affected zone, potentially reducing the load-bearing capacity due to the penetration depth of the hardface layer or the buffer layer. Robotization of hardfacing creates equal layers with high precision, which helps the precise comparison. In this study, S690QL and S960QL substrates were investigated under different heat inputs, and the impact properties of these specimens were tested. Instrumented impact test results were analyzed and supplemented with surface fractography. The impact resistance of the S690QL substrate decreases with higher heat input and penetration depth. In contrast, S960QL exhibits different behavior: the use of lowest heat input causes a 226 % increase in impact energy compared with the base material. The underlying reasons for this were identified through force-time curve analysis, where the positive effect of the heat-affected zone is determined. Additionally, the maximum impact forces display different behavior for the two materials: S960QL shows higher impact force except in case of highest heat input, where the S690QL shows better force. These findings are valuable for selecting the appropriate substrate and hardfacing technology for this application and its specific loading conditions.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100314"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144124951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-05-09DOI: 10.1016/j.jajp.2025.100307
Sebastian Platt , Jan Wegner , Arno Elspaß , Hanna Schönrath , Stefan Kleszczynski
Parts produced via powder bed fusion of metal using a laser beam process often exhibit mechanical anisotropy due to the directional solidification, complicating part design. This study explores the use of ultrasonic-assistance to reduce anisotropy by promoting microstructural homogenization through increased nucleation. Specimens were fabricated using a dual exposure strategy, to avoid the challenges that arise with the in-situ ultrasonic excitation of a powder bed. Furthermore, a comprehensive microstructural as well as mechanical analysis was carried out. Microstructural analysis revealed increased grain orientation variation in ultrasonically treated specimens. Mechanical testing showed improved tensile and yield strength and reduced anisotropy, with tensile and yield strength anisotropy decreasing by 55.4 % and 46.1 %, respectively. Despite increased surface roughness, ultrasonic treatment reduced anisotropy in ductility-related properties, highlighting its potential to improve the performance of additively manufactured parts by reducing anisotropy and simultaneously enhancing mechanical properties.
{"title":"Enhancing mechanical properties and isotropy in ultrasonic assisted powder bed fusion of metals using a laser beam (PBF-LB/M) via Dual Exposure","authors":"Sebastian Platt , Jan Wegner , Arno Elspaß , Hanna Schönrath , Stefan Kleszczynski","doi":"10.1016/j.jajp.2025.100307","DOIUrl":"10.1016/j.jajp.2025.100307","url":null,"abstract":"<div><div>Parts produced via powder bed fusion of metal using a laser beam process often exhibit mechanical anisotropy due to the directional solidification, complicating part design. This study explores the use of ultrasonic-assistance to reduce anisotropy by promoting microstructural homogenization through increased nucleation. Specimens were fabricated using a dual exposure strategy, to avoid the challenges that arise with the in-situ ultrasonic excitation of a powder bed. Furthermore, a comprehensive microstructural as well as mechanical analysis was carried out. Microstructural analysis revealed increased grain orientation variation in ultrasonically treated specimens. Mechanical testing showed improved tensile and yield strength and reduced anisotropy, with tensile and yield strength anisotropy decreasing by 55.4 % and 46.1 %, respectively. Despite increased surface roughness, ultrasonic treatment reduced anisotropy in ductility-related properties, highlighting its potential to improve the performance of additively manufactured parts by reducing anisotropy and simultaneously enhancing mechanical properties.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100307"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143921669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flux-cored arc welding (FCAW) generates hazardous byproducts such as welding fumes and hexavalent chromium (Cr(VI)), posing significant health and environmental risks. This study investigated the effectiveness of modifying specific flux components in flux-cored wires (FCWs) to reduce these emissions. One base FCW and ten flux-modified FCWs were tested under controlled conditions, capturing emissions for gravimetric and Cr(VI) analysis. Flux compositions were determined using X-ray fluorescence. Statistical analyses, including difference tests, correlation, and multiple linear regression, were conducted to evaluate the association between the content of flux components and emission rates. Sodium (Na) content in the flux was positively associated with increased emission of welding fumes and Cr(VI), while titanium (Ti) content showed a negative association. Increasing the contents of fluorine (F), potassium (K), and chromium (Cr) in the flux raised welding fume emission but reduced Cr(VI) emissions. Strategic adjustments in flux composition, specifically increasing Ti, silicon (Si) and zirconium (Zr) while decreasing Cr, K, Na, and F content, significantly reduced welding fume emissions by up to 32.4 % and Cr(VI) emissions by 95.4 %. These findings suggest that tailoring flux composition can effectively mitigate occupational and environmental hazards, enhance welder safety, and promote more sustainable FCAW practices without compromising welding performance.
{"title":"Tailoring flux composition to control welding fume and hexavalent chromium emissions in flux cored arc welding","authors":"Sungyo Jung , Gi Taek Oh , Seungjin Jung , Chungsik Yoon","doi":"10.1016/j.jajp.2025.100311","DOIUrl":"10.1016/j.jajp.2025.100311","url":null,"abstract":"<div><div>Flux-cored arc welding (FCAW) generates hazardous byproducts such as welding fumes and hexavalent chromium (Cr(VI)), posing significant health and environmental risks. This study investigated the effectiveness of modifying specific flux components in flux-cored wires (FCWs) to reduce these emissions. One base FCW and ten flux-modified FCWs were tested under controlled conditions, capturing emissions for gravimetric and Cr(VI) analysis. Flux compositions were determined using X-ray fluorescence. Statistical analyses, including difference tests, correlation, and multiple linear regression, were conducted to evaluate the association between the content of flux components and emission rates. Sodium (Na) content in the flux was positively associated with increased emission of welding fumes and Cr(VI), while titanium (Ti) content showed a negative association. Increasing the contents of fluorine (F), potassium (K), and chromium (Cr) in the flux raised welding fume emission but reduced Cr(VI) emissions. Strategic adjustments in flux composition, specifically increasing Ti, silicon (Si) and zirconium (Zr) while decreasing Cr, K, Na, and F content, significantly reduced welding fume emissions by up to 32.4 % and Cr(VI) emissions by 95.4 %. These findings suggest that tailoring flux composition can effectively mitigate occupational and environmental hazards, enhance welder safety, and promote more sustainable FCAW practices without compromising welding performance.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100311"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2024-12-25DOI: 10.1016/j.jajp.2024.100275
Shoeib Karami , Mohammad Yousefieh , Homam Naffakh-Moosavy
In this study, the key findings of evaluating laser beam welding parameters on the multi-layered structure of 6061 aluminum alloys fabricating by accumulative roll bonding process are reported, considering fostering mechanical properties concerning the influence of filler metal and welding speed on the weld bead quality by taking into account reducing welding defects. Welding defects, including porosity and hot cracks, formed due to the evaporation of low-molten elements such as Mg, which can be reduced by adding filler metal to compensate for the vaporized Mg content. The optimal tensile strength is related to the laser beam welding using filler metal at the speed of 40 mm/s. Work-hardening behavior leading to fatigue life improvement is associated with the rearrangement and multiplication of dislocations in all samples. The related mechanisms responsible for the microstructural evolution during the cyclic deformation process were described by transmission electron microscopy observation. The fracture surface analyzed by scanning electron microscopy indicated that delamination contributing to local necking is the leading cause of fracture in accumulative roll-bonded 6061 aluminum alloy. However, the fracture morphology of laser-welded samples displays a heterogeneous distribution of equiaxed dimples along with negligible serpentine sliding, indicating a ductile fracture mode.
{"title":"The effect of laser welding parameters on mechanical properties and microstructure evolution of multi-layered 6061 aluminum alloy","authors":"Shoeib Karami , Mohammad Yousefieh , Homam Naffakh-Moosavy","doi":"10.1016/j.jajp.2024.100275","DOIUrl":"10.1016/j.jajp.2024.100275","url":null,"abstract":"<div><div>In this study, the key findings of evaluating laser beam welding parameters on the multi-layered structure of 6061 aluminum alloys fabricating by accumulative roll bonding process are reported, considering fostering mechanical properties concerning the influence of filler metal and welding speed on the weld bead quality by taking into account reducing welding defects. Welding defects, including porosity and hot cracks, formed due to the evaporation of low-molten elements such as Mg, which can be reduced by adding filler metal to compensate for the vaporized Mg content. The optimal tensile strength is related to the laser beam welding using filler metal at the speed of 40 mm/s. Work-hardening behavior leading to fatigue life improvement is associated with the rearrangement and multiplication of dislocations in all samples. The related mechanisms responsible for the microstructural evolution during the cyclic deformation process were described by transmission electron microscopy observation. The fracture surface analyzed by scanning electron microscopy indicated that delamination contributing to local necking is the leading cause of fracture in accumulative roll-bonded 6061 aluminum alloy. However, the fracture morphology of laser-welded samples displays a heterogeneous distribution of equiaxed dimples along with negligible serpentine sliding, indicating a ductile fracture mode.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100275"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-01-02DOI: 10.1016/j.jajp.2024.100278
Nagaraju Doredla, Senthil Kumar N
Ferrite-Pearlite (α-P) steels like E350 steel were extensively used in pre-engineered structures like industrial warehouses, bridges, etc., owing to their special ductility property. Submerged arc welding is highly efficient in welding long-span prefabricated structures. In this paper, weld overlay and butt weld experimental investigations were performed to optimise the welding process by understanding the influence of heat input on residual stress generation, weld efficiency, microstructural and mechanical characteristics of the weld joint to match the filler wire with the base material characteristics. Trail runs were conducted using the Taguchi design optimisation approach. Taguchi method is useful to standardise and simplify the use of design of experiments. The weld quality was evaluated using non-destructive evaluations. Residual stress was tensile near the weld and transitioned to compressive further from the root. The intensity of residual stress decreased gradually with an increase in transverse distance from the weld root. Acicular ferrite, polygonal ferrite, and traces of lath bainite microstructure were observed in the weld zone. The weld microstructure became coarser toward the melting boundary of the welded joint with an increase in heat input greater than 1.09 kJ/mm. A notable decrease in weld brittleness was observed with an increase in heat input from 1.09–1.37 kJ/mm, and the fracture initiated away from the weld with ductile and quasi-ductile cleavages. The overall microstructure and mechanical characteristics of the welded joint were improved at a controlled heat input of 1.09–1.37 kJ/mm.
{"title":"Determination of heat input impact on residual stress, microstructure and mechanical characteristics of welded ferrite-pearlite (α-P) steel joints by using taguchi optimization approach","authors":"Nagaraju Doredla, Senthil Kumar N","doi":"10.1016/j.jajp.2024.100278","DOIUrl":"10.1016/j.jajp.2024.100278","url":null,"abstract":"<div><div>Ferrite-Pearlite (α-P) steels like E350 steel were extensively used in pre-engineered structures like industrial warehouses, bridges, etc., owing to their special ductility property. Submerged arc welding is highly efficient in welding long-span prefabricated structures. In this paper, weld overlay and butt weld experimental investigations were performed to optimise the welding process by understanding the influence of heat input on residual stress generation, weld efficiency, microstructural and mechanical characteristics of the weld joint to match the filler wire with the base material characteristics. Trail runs were conducted using the Taguchi design optimisation approach. Taguchi method is useful to standardise and simplify the use of design of experiments. The weld quality was evaluated using non-destructive evaluations. Residual stress was tensile near the weld and transitioned to compressive further from the root. The intensity of residual stress decreased gradually with an increase in transverse distance from the weld root. Acicular ferrite, polygonal ferrite, and traces of lath bainite microstructure were observed in the weld zone. The weld microstructure became coarser toward the melting boundary of the welded joint with an increase in heat input greater than 1.09 kJ/mm. A notable decrease in weld brittleness was observed with an increase in heat input from 1.09–1.37 kJ/mm, and the fracture initiated away from the weld with ductile and quasi-ductile cleavages. The overall microstructure and mechanical characteristics of the welded joint were improved at a controlled heat input of 1.09–1.37 kJ/mm.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100278"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-01Epub Date: 2025-05-14DOI: 10.1016/j.jajp.2025.100309
O Kachouri, J Bardon, D Ruch, A Laachachi
The emergence of debonding technologies has enabled adhesive systems to better align with the principles of sustainability and the circular economy by addressing the gap between the end-of-life stage of adhesively bonded products and the potential for component reuse. In this context, the present study explores the application of thermally responsive additives to induce controlled debonding in adhesive joints. In our previous investigations, it was shown that integrating various types of flame retardants (intumescent and non-intumescent) significantly reduced the debonding temperature, by altering the thermomechanical properties of the joint at temperatures substantially lower than the degradation onset of the unmodified adhesive system. Expandable graphite (EG), a thermally responsive material, has previously been employed with success for similar purposes. Its incorporation into the adhesive layer, even in trace amounts, results in a very significant expansion upon the application of heat, thereby providing an effective mechanism for disassembling adhesively bonded structural assemblies. The present study builds on this prior research and probes deeper into the manufacturing processes underlying EG. The primary hypothesis explored is whether tailoring these processes can result in modulating the thermal response of adhesives modified by EG, thereby achieving debonding at distinct temperature ranges suitable for a wide spectrum of applications. This study investigates EG-modified adhesives, assessing their mechanical properties, thermomechanical degradation, and microstructural changes using characterization techniques such as pull-off tests, microtomography, TGA, and DMA. Finally, the recycling potential is demonstrated through the successful reuse of debonded substrates after a simple cleaning process.
{"title":"Controlling debond on demand performance in adhesive systems using structurally tuned expandable graphite fillers","authors":"O Kachouri, J Bardon, D Ruch, A Laachachi","doi":"10.1016/j.jajp.2025.100309","DOIUrl":"10.1016/j.jajp.2025.100309","url":null,"abstract":"<div><div>The emergence of debonding technologies has enabled adhesive systems to better align with the principles of sustainability and the circular economy by addressing the gap between the end-of-life stage of adhesively bonded products and the potential for component reuse. In this context, the present study explores the application of thermally responsive additives to induce controlled debonding in adhesive joints. In our previous investigations, it was shown that integrating various types of flame retardants (intumescent and non-intumescent) significantly reduced the debonding temperature, by altering the thermomechanical properties of the joint at temperatures substantially lower than the degradation onset of the unmodified adhesive system. Expandable graphite (EG), a thermally responsive material, has previously been employed with success for similar purposes. Its incorporation into the adhesive layer, even in trace amounts, results in a very significant expansion upon the application of heat, thereby providing an effective mechanism for disassembling adhesively bonded structural assemblies. The present study builds on this prior research and probes deeper into the manufacturing processes underlying EG. The primary hypothesis explored is whether tailoring these processes can result in modulating the thermal response of adhesives modified by EG, thereby achieving debonding at distinct temperature ranges suitable for a wide spectrum of applications. This study investigates EG-modified adhesives, assessing their mechanical properties, thermomechanical degradation, and microstructural changes using characterization techniques such as pull-off tests, microtomography, TGA, and DMA. Finally, the recycling potential is demonstrated through the successful reuse of debonded substrates after a simple cleaning process.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100309"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144124952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study is focused on improving the joint strength of AA7075-T6 specimens with aluminium cladding (alclad) joined through the refill friction stir spot welding (RFSSW) process. The bonding ligament weakens the RFSSW joint because the alclad layer is trapped between the specimens. This layer hinders material mixing during welding and creates a weak interface prone to crack initiation and propagation during external loading, affecting joint integrity. To overcome this problem, a novel tool sequencing variant of RFSSW, the pin plunging reinforced RFSSW (PPRSP-RFSSW), is proposed. A smoothed-particle hydrodynamics (SPH) formulation-based 3D thermo-mechanical model is developed to study the thermo-mechanical and material flow properties as it is possible to trace the field variables explicitly; it can manage significant material/elemental deformations and capture material mixing dynamically. The PPRSP-RFSSW is numerically analyzed and compared to existing sleeve plunging RFSSW (SP-RFSSW). The numerical model's accuracy was tested by comparing temperatures to experimental temperature data in published papers, and the results corresponded well. Comparisons are made between the SP-RFSSW and PPRSP-RFSSW concerning their heat distribution, plasticization, and material flow. Enhanced material mixing and plasticization were observed through PPRSP-RFSSW, and this tool sequencing is recommended for joining alclad AA7075-T6 specimens.
{"title":"Thermo-mechanical and material flow characteristics of tool sequencing dynamics in refill FSSW of thin alclad AA7075-T6 sheets: Numerical analysis using meshless smoothed-particle hydrodynamics method","authors":"Venkata Somi Reddy Janga, Mokhtar Awang, Nabihah Sallih, Tamiru Alemu Lemma","doi":"10.1016/j.jajp.2025.100285","DOIUrl":"10.1016/j.jajp.2025.100285","url":null,"abstract":"<div><div>This study is focused on improving the joint strength of AA7075-T6 specimens with aluminium cladding (alclad) joined through the refill friction stir spot welding (RFSSW) process. The bonding ligament weakens the RFSSW joint because the alclad layer is trapped between the specimens. This layer hinders material mixing during welding and creates a weak interface prone to crack initiation and propagation during external loading, affecting joint integrity. To overcome this problem, a novel tool sequencing variant of RFSSW, the pin plunging reinforced RFSSW (PPRSP-RFSSW), is proposed. A smoothed-particle hydrodynamics (SPH) formulation-based 3D thermo-mechanical model is developed to study the thermo-mechanical and material flow properties as it is possible to trace the field variables explicitly; it can manage significant material/elemental deformations and capture material mixing dynamically. The PPRSP-RFSSW is numerically analyzed and compared to existing sleeve plunging RFSSW (SP-RFSSW). The numerical model's accuracy was tested by comparing temperatures to experimental temperature data in published papers, and the results corresponded well. Comparisons are made between the SP-RFSSW and PPRSP-RFSSW concerning their heat distribution, plasticization, and material flow. Enhanced material mixing and plasticization were observed through PPRSP-RFSSW, and this tool sequencing is recommended for joining alclad AA7075-T6 specimens.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100285"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Continuous drive friction welding (CDFW) is a highly efficient technique for fabricating large Polyether-ether-ketone (PEEK) components. However, the bending strength of welded specimens is often constrained by the formation of pores at the weld interface. Addressing this limitation, this study aims to enhance the bending strength of PEEK polymer cylinders by applying ultrasound-assisted continuous drive friction welding (UACDFW). To further improve joint performance, a novel post-compression technique is introduced and used after the welding process to increase the weld-bonded area. Additionally, image processing software is employed to evaluate and analyze the weld-bonded area ratio, comprehensively assessing the interfacial characteristics. Optimizing CDFW parameters increased the bending strength of the welded components from 201.6 MPa to 380.8 MPa and the joint area ratio from 77.54 % to 99.99 %. The optimized parameters include a rotational speed of 4000 rpm, a preheating time of 5 s, and a post-compression feed rate of 3.2 mm/s. The results demonstrate the potential of UACDFW and post-compression techniques as effective solutions for improving the mechanical performance and reliability of PEEK components in high-performance applications.
{"title":"Enhancing the weld quality of polyetheretherketone polymer cylinders using reducing pores in the weld interface","authors":"Chil-Chyuan Kuo , Xiao-Ze Xie , Chong-Xu Liao , Wen-Bin Huang , Yu-Jie Chen , Armaan Farooqui , Song-Hua Huang , Shih-Feng Tseng","doi":"10.1016/j.jajp.2025.100281","DOIUrl":"10.1016/j.jajp.2025.100281","url":null,"abstract":"<div><div>Continuous drive friction welding (CDFW) is a highly efficient technique for fabricating large Polyether-ether-ketone (PEEK) components. However, the bending strength of welded specimens is often constrained by the formation of pores at the weld interface. Addressing this limitation, this study aims to enhance the bending strength of PEEK polymer cylinders by applying ultrasound-assisted continuous drive friction welding (UACDFW). To further improve joint performance, a novel post-compression technique is introduced and used after the welding process to increase the weld-bonded area. Additionally, image processing software is employed to evaluate and analyze the weld-bonded area ratio, comprehensively assessing the interfacial characteristics. Optimizing CDFW parameters increased the bending strength of the welded components from 201.6 MPa to 380.8 MPa and the joint area ratio from 77.54 % to 99.99 %. The optimized parameters include a rotational speed of 4000 rpm, a preheating time of 5 s, and a post-compression feed rate of 3.2 mm/s. The results demonstrate the potential of UACDFW and post-compression techniques as effective solutions for improving the mechanical performance and reliability of PEEK components in high-performance applications.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"11 ","pages":"Article 100281"},"PeriodicalIF":3.8,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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