Keyhole stability, arc behavior, and molten pool flow in narrow-gap oscillating laser-arc hybrid welding of titanium alloy

Yu, Jie; Cai, Chuang; Xie, Jia; Chen, Zilin; Chen, Hui

doi:10.1016/j.ijheatmasstransfer.2023.124922

Cited by 16 publications

(4 citation statements)

References 33 publications

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“…However, when the laser power was too high or the welding speed was too low, the stability of keyhole would decrease [16,31]. At this time, in the welding process, the keyhole moves forward, the rear wall of the keyhole collapses, and the gas (shielding gas and metal vapor) that has not yet escaped will be sealed in the weld joint, eventually forming a porosity [33].…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Microstructure, Variant Selection, and Mechanical Properties of Laser-Welded Ti-4Al-2V Joints

Zhu,

Lu,

Zhang

et al. 2024

Metals

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Laser welding of the near α-phase titanium alloy Ti-4Al-2V, used for complex components in the nuclear industry, has been rarely reported. In this study, butt weld joints made of Ti-4Al-2V alloy plates under different parameters, including the laser power, the welding speed, and the defocus distance, were manufactured and analyzed. The results showed that adjusting the combination of 4.2 kW of laser power, a 20 mm/s welding speed, and a −2 mm defocus distance could achieve a penetration depth exceeding 6 mm. Porosity defects were prone to forming in the middle and bottom parts of the fusion zone, due to rapid cooling. The microstructure of the fusion zone was mainly needle-like α martensite, which precipitated in the form of specific clusters. The interior of a cluster was composed of three types of variants with <11−20>/60° phase interfaces to achieve the lower boundary’s energy. Affected by the microstructure and welding defects, the strength of the weld joint was basically similar under different welding conditions, namely about 720 MPa, slightly higher than that of the base metal, while the rupture elongation at breaking decreased by more than 50%. The micro-Vickers hardness of the weld joints was about 50–60 HV higher than that of the base metal, while the impact toughness was about 40 KJ, almost half that of the base metal. This research lays a solid foundation for the engineering application of laser welding of Ti-4Al-2V alloys.

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Section: Mechanical Propertiesmentioning

confidence: 99%

Microstructure, Variant Selection, and Mechanical Properties of Laser-Welded Ti-4Al-2V Joints

Zhu,

Lu,

Zhang

et al. 2024

Metals

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“…Figure 8 shows the macro-morphology of the welded joint and SEM images of different regions under optimal process parameters. Figure 8a shows the microstructure of the welded joint divided into the following three regions: the welding metal zone (WZ), the heat-affected zone (HAZ), and the base metal (BM) [8,20]. The regions were symmetrical left and right, with the weld seam as the center.…”

Section: Microstructure Of the Welded Jointmentioning

confidence: 99%

“…As a form of near-α titanium alloy [3,4], TA15 titanium alloy combines the α phase, which has the weldability and thermal strength of titanium alloys, and the β phase, which possesses the plasticity of dual-phase titanium alloys and has been widely used in aircraft frame structural components [5][6][7]. In the manufacturing process of titanium alloy components for aviation, welding technology has become indispensable because welding structures are simple, material-saving, and have high reliability, which can achieve high-quality, efficient, and low-cost manufacturing [8,9]. However, because of the metallurgical properties of titanium alloys, welding defects such as pores and cracks are prone to occur during the welding process, which could cause stress concentration, weaken the strength of the welded joints, reduce fatigue performance, and damage structural sealing performance [10].…”

Section: Introductionmentioning

confidence: 99%

Tailoring Weldability for Microstructures in Laser-Welded Near-α Titanium Alloy: Insights on Mechanical Properties

Zhang,

Cong,

Zeng

et al. 2024

Metals

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With the development of lightweight aerospace structures, the use of the high-quality and efficient laser welding of near-α titanium alloys has received widespread attention and favor thanks to its superior comprehensive performance. The welding experiment of 3 mm thick TA15 titanium alloy was carried out by YAG laser welding, and the material weldability, microstructure, microhardness, and mechanical properties of welded joints were systematically studied. The results indicated that laser welding of TA15 titanium alloy can produce well-formed welded joints without defects such as cracks and porosity. The welded metal used was a typical basket-weave microstructure composed of a large number of α′ martensitic phases and a small number of high-temperature residual β phases, and the heat-affected zone was a staggered arrangement of undissolved α phase and needle-like α′ martensite. The microhardness of the welded joint showed a hump distribution, and the hardness of WM fluctuated between 410 and 450 HV since the martensitic transformation occurred during the solidification of the weld under thermal cycling, and the β phase changed to the needle-like α′ phase. The tensile test indicated that the fracture position was located in the base metal area, and the fracture morphology showed the equiaxial dimple morphology of different sizes in a ductile fracture mode. The welded metal had the lowest impact performance (average value of 5.3 J) because the weld area was predominantly coarse α′ martensite. This experiment conducted systematic, in-depth, and extensive research on welding processes, hardness, tensile, impact, and fracture mechanisms. Based on the special product applications in the aerospace field, it was more targeted and conducive to promoting the application of the welding process in this material.

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“…However, scholars mostly focus on the study of thin titanium alloys. For large thick plates, some scholars adopt narrow-gap laser-arc hybrid welding and beam shaping to improve the weld formation and performance [25,26], but there are still few studies on the laser-MIG hybrid welding parameters and their effects on the joint performance of TC4 medium-thick cross-section alloy, so further studies are needed [9]. In this study, the feasibility and mechanical performance of laser-MIG hybrid welding for joining medium-thick titanium alloy plates is investigated.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Impact Toughness of Laser-Arc Hybrid Welded Joint of Medium-Thick TC4 Titanium Alloy

Luo,

Feng,

et al. 2024

Coatings

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This study delves into the impact toughness of medium-thick (12 mm thick) titanium alloy joints crafted through a multi-layer, multi-pass welding technique that blends laser-arc (MIG) hybrid welding technology. Microstructural scrutiny, employing optical microscopy, SEM and TEM, unveils a consistent composition across weld passes, with prevailing α/α′ phases interspersed with some β phase, resulting in basket-weave structures primarily dominated by acicular α′ martensite. However, upper regions exhibit Widmanstatten microstructures, potentially undermining joint toughness. Hardness testing indicates higher values in cosmetic layers (~420 HV) compared to backing layers and bending tests manifest superior toughness in lower joint regions, attributed to smaller grain sizes induced by repetitive welding thermal cycles. Impact toughness assessment unveils diminished values in the weld metal (WM) compared to the heat-affected zone (HAZ) and base material (BM), amounting to 91.3% of the base metal’s absorption energy. This decrement is ascribed to heightened porosity in upper regions and variations in grain size and phase composition due to multi-layer, multi-pass welding. Microstructural analysis proximal to failure sites suggests one mechanism wherein crack propagation is impeded by the β phase at acute crack angles. In essence, this study not only underscores the practicality of laser-MIG hybrid welding for medium-thick TC4 alloy plates but also underscores the reliability of joint mechanical properties.

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Keyhole stability, arc behavior, and molten pool flow in narrow-gap oscillating laser-arc hybrid welding of titanium alloy

Cited by 16 publications

References 33 publications

Microstructure, Variant Selection, and Mechanical Properties of Laser-Welded Ti-4Al-2V Joints

Microstructure, Variant Selection, and Mechanical Properties of Laser-Welded Ti-4Al-2V Joints

Tailoring Weldability for Microstructures in Laser-Welded Near-α Titanium Alloy: Insights on Mechanical Properties

Microstructure and Impact Toughness of Laser-Arc Hybrid Welded Joint of Medium-Thick TC4 Titanium Alloy

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