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Effects of Performance Measures of Non-conventional Joining Processes on Mechanical Properties of Metal Matrix Composites
Published in Suneev Anil Bansal, Virat Khanna, Pallav Gupta, Metal Matrix Composites, 2023
Kamaljit Singh, Suneev Anil Bansal, Virat Khanna, Satinder Singh
As shown in Figure 7.7, in laser beam welding, a laser is utilized to join different materials together through fusion. In this process, the mating surfaces of the materials are melted by the high intensity of the laser causing the molten metal to intermix and solidify after the removal of the heating source (Kalaiselvan et al., 2021). Laser beam welding can produce high-quality components due to its ability to generate controlled heat at alocalized area. Moreover, the weld produced through laser beam welding has another advantage over arc welds, in that it changes mechanical properties at the weld to a limit and shows less deterioration on the workpiece. This is attributable to the fact that laser welding causes very small heat-affected zones due to its intense focused beam (Guo et al., 2012a). There is no direct physical contact between the head and workpiece, so the rapid welding process makes it even more effective (Banerjee et al., 2016; Dai et al., 2019).
Solid Materials: Joining Processes
Published in Leo Alting, Geoffrey Boothroyd, Manufacturing Engineering Processes, 2020
Laser beam welding is a metal joining process that produces melting of materials with the heat obtained from a narrow beam of coherent, monochromatic light. This beam can travel long distances without attenuation and may be focused through lenses to produce spots in which the energy density amounts to over 1012 W/m2 and is equaled only by the electron beam. No vacuum chamber is required for the generation and delivery of the beam, which is generated in a laser medium (gas: CO2; solids: Nd-YAG), each type having specific characteristics. The laser output can be pulsed or continuous. Shielding gas blown through a nozzle most often coaxially with the beam protects the weld. Typically, no filler material is used.
Contemporary Machining Processes for New Materials
Published in E. S. Gevorkyan, M. Rucki, V. P. Nerubatskyi, W. Żurowski, Z. Siemiątkowski, D. Morozow, A. G. Kharatyan, Remanufacturing and Advanced Machining Processes for New Materials and Components, 2022
E. S. Gevorkyan, M. Rucki, V. P. Nerubatskyi, W. Żurowski, Z. Siemiątkowski, D. Morozow, A. G. Kharatyan
The laser welding process is not only easily automated, but various real-time monitoring technologies can be applied for improving welding efficiency and guaranteeing the quality of joint products. An extensive review provided by Cai, Wang et al. (2020) distinguishes three different parts of the monitoring: pre-processing scanning, in-process monitoring, and post-process diagnosing. The pre-process scanning mainly focuses on the joint gap between workpieces and seam tracking problems to ensure the central position of the laser beam spot in the gap and thus to obtain reliable joints. The real-time in-process monitoring is concentrated on welding zone characteristics such as keyhole, molten pool, plasma, and spatters. Based on the analysis of dynamic changes of these characteristics, the quality of a weld seam can be adjusted using AI-based methods. The post-process diagnostics is focused on defects like pores, cracks, spatters, surface collapses, underfills, etc., which are critical indicators of the weld seam quality. Among the various sensing techniques, the authors present acoustic emission measurement, optical signal, and thermal signal. Novel monitoring methods, such as X-ray imaging, in-line coherent imaging, and magnetooptical imaging were demonstrated to achieve excellent results. However, a welding situation can be reflected more effectively and comprehensively when multi-sensor fusion technology is applied and full advantage is taken of various signal sensors. Vision sensors are at the core of this technology, so that in an established monitoring system, an optical sensor can be combined with a vision sensor, an X-ray system with a high-speed camera, a sound sensor assembled with a vision sensor, etc. In order to achieve various monitoring objectives, such as parameter optimization, feature prediction, seam tracking, defects classification, simulation validation or adaptive control, a variety of AI techniques can be applied (Cai, 2020). Laser beam welding is a high-quality fusion joining process that enables the welding of dissimilar components, e.g., titanium alloys with various counterparts including steel, aluminum, magnesium, nickel, niobium, copper, etc. (Quazi et al., 2020). It has also been reported that femtosecond laser pulses at high repetition rates can be used to weld glasses of different combinations (Richter, 2016).
Enhancement of metallurgical and mechanical properties due to grain refinement in the compressive residual stress developed surface after the laser shock peening process: a review
Published in Canadian Metallurgical Quarterly, 2023
Welding is the process of joining metals together, either by melting and fusing them directly or by using a filler metal to facilitate the joining [41–44]. Numerous researchers have studied the advantages of laser shock peening over weldments, and Table 3 indicates some of the notable works. When processing laser shock peening over welding, the base metal undergoes various microstructural, thermal, metallurgical, and mechanical changes. Compared to traditional welding processes such as TIG welding and MIG welding, laser beam welding has peculiar properties such as non-contact less work, a fusion region with refined grains, elevated welding speed, absence of a heat affected zone and improved mechanical properties. In the aerospace and automobile industries, hybrid joints are required to produce high-quality weldments, which can be achieved with the laser beam welding process. Surface improvement methods such as the laser shock peening process help avoid issues such as weakening of the weld region, porosity, and hot cracking created owing to the formation of harmful intermetallics after the conventional welding process.
Laser and hybrid laser welding of type 316L(N) austenitic stainless steel plates
Published in Materials and Manufacturing Processes, 2020
The laser beam possesses a higher power density than arc which helps in achieving maximum depth of penetration autogenously in a single pass. Laser welding process has more benefits namely low heat input, narrow HAZ, no filler wire usage, no groove preparation, low residual stress, low distortion and faster welding speed which altogether result in higher quality and productivity. However, laser beam welding has some limitations such as porosity formation, requirement for stringent clamping, higher power capacity for welding high thickness components and cracking due to faster cooling rates. The shortcomings of the laser welding can be surmounted by coupling another heat source to the laser and this resulted in the development of a new advanced welding process called hybrid laser welding process.
The synergy between powder metallurgy processes and welding of metallic alloy: a review
Published in Powder Metallurgy, 2020
Ayorinde Tayo Olanipekun, Nthabiseng Beauty Maledi, Peter Madindwa Mashinini
Laser welding processes have gained prominence over the years in welding different metallic alloys. These processes are characterised by high welding speeds, precision and high efficiencies. Moreover, laser welding is associated with low heat input which result in low thermal distortion, residual stresses and deformation compared to other welding techniques [4,31–36]. Laser beam welding (LBW) uses laser beam to melt and join metals. The laser beam is either solid-state laser or gas [37] as shown in Figure 4. Notably, types of main laser used for welding are CO2 laser, YAG laser, lamp-pumped, Laser diode (LD), LD-pumped solid state laser, disc laser, and fiber laser [38].