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Amirhossein Sadeghian

Bio: Amirhossein Sadeghian is an academic researcher from Coventry University. The author has contributed to research in topics: Materials science & Welding. The author has an hindex of 3, co-authored 5 publications receiving 54 citations. Previous affiliations of Amirhossein Sadeghian include Amirkabir University of Technology.

Papers
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Journal ArticleDOI
TL;DR: In this article, the fundamental difficulties and latest developments in dissimilar laser welding of steel-copper, steel-aluminum, aluminum-coppers, and steel-nickel are reviewed.
Abstract: The electric vehicle (EV) battery systems are complex assemblies of dissimilar materials in which battery cells are connected using several thousand interconnect joints. Every single joint influences the functionality and efficiency of the whole battery system, making the joining process crucial. Laser welding is considered a desirable choice for EV battery manufacturing due to its non-contact nature, high energy density, precise control over the heat input, and ease of automation. However, incompatible thermos-physical properties of dissimilar materials used in battery tabs and interconnectors pose a significant challenge for achieving complete metallurgical bond. Furthermore, the formation of undesirable weld microstructures such as hard and brittle intermetallic compounds (IMCs) substantially undermines the structural, electrical, and thermal characteristics of battery joints. This paper reviews the fundamental difficulties and latest developments in dissimilar laser welding of steel-copper, steel-aluminum, aluminum-copper, and steel-nickel, some of the potential joint combinations in EV battery pack manufacturing. The weld microstructure and common metallurgical defects, as well as mechanical and electrical properties of joints are discussed. In addition, the effects of laser welding process parameters on the joint properties and the applicability of various interlayers and coatings in laser welding of battery materials are assessed.

65 citations

Journal ArticleDOI
TL;DR: The phase transformation during diffusion brazing of high chromium Ni-based Inconel 939 superalloy, using a ternary Ni-14.9 Cr-3.7 B (wt.%) interlayer was studied as mentioned in this paper.

35 citations

Journal ArticleDOI
TL;DR: In this article, the applicability of the diffusion brazing technique for joining IN-939 superalloy using a Ni-Cr-B interlayer was assessed, and the phases formed during the basting process in the isothermally solidified zone (ISZ), athermally sealed zone (ASZ), and diffusion affected zone (DAZ) were studied.

33 citations

Journal ArticleDOI
TL;DR: In this article, the applicability of transient liquid phase bonding technique to join a nickel-based precipitation-hardened superalloy (Inconel 939) to a solid-solutionhardened one (inconel 625) to avoid the limitations of other joining techniques such as fusion welding was evaluated.

23 citations

Journal ArticleDOI
TL;DR: In this article, the microstructure and mechanical properties of transient liquid phase (TLP) bonded joints between dissimilar precipitation hardened IN939 and solid solution hardened IN625 with a Ni-Cr-Si-Fe-B filler alloy were studied.
Abstract: The microstructure and mechanical properties of transient liquid phase (TLP) bonded joints between dissimilar precipitation hardened IN939 and solid solution hardened IN625 with a Ni-Cr-Si-Fe-B filler alloy were studied. The TLP bonding was conducted in different bonding times (i.e., 15, 25, 35, 45, 60, and 90 minutes). Different phases, formed in the isothermally solidified zone (ISZ), on-cooling solidified zone, and diffusion affected zone (DAZ), were characterized using EDS, XRD, and EPMA analyses. A Ni-rich γ solid solution, CrB, and Ni3B were detected in the centerline of samples with incomplete isothermal solidification (i.e., 15 and 25 minutes), formed by binary and ternary eutectic reactions. Raising the time of bonding boosted isothermal solidification, resulting in a joint without deleterious eutectic microconstituents in bonding times of 35 minutes and higher. Chromium-rich borides were discovered in the DAZ of IN939, while the IN625-DAZ side was composed of chromium-molybdenum-rich borides. The concentration of alloying elements in the ISZ experienced an increment by further raising the bonding time to 90 minutes, creating a more homogenous bond with increased ISZ microhardness and mechanical properties. The highest shear strength (~ 92 and ~ 77 Pct that of the IN939 and IN625, respectively) and failure energy were attained for the 90-minutes sample. The fracture mechanism was also switched from a brittle semi-cleave morphology to a more ductile dimple-like morphology by increasing the bonding time from 15- to 90-minutes.

6 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a critical review on the state-of-the-art for the welding of high entropy alloys (HEAs) related materials is provided, aiming to address the weldability of HEAs under the compositional diversity, different initial states, welding processes and parameters, joint configurations and service conditions.

40 citations

Journal ArticleDOI
TL;DR: In this article, the effects of different transient liquid phase (TLP) bonding times on the microstructure and mechanical properties of Hastelloy X joints made by Ni-Cr-B-Si-Fe filler alloy were investigated.
Abstract: The effects of different transient liquid phase (TLP) bonding times on the microstructure and mechanical properties of Hastelloy X joints made by Ni–Cr–B–Si–Fe filler alloy were investigated. The specimens were TLP bonded at 1070 °C for holding times of 5, 20, 80, 320, and 640 min. The electron probe microanalysis (EPMA) results revealed that the main eutectic phases observed at the joints following incomplete isothermal solidification were Ni-rich borides, Ni-rich silicides, Ni–Si eutectic, and some Cr-rich borides. A high density of plate-like, blocky, and acicular (Mo and Cr)-rich borides were observed in the diffusion-affected zone (DAZ) of the samples; however, increasing the holding time decreased the contents of these phases. The solid-state diffusion was found to be a more effective transportation phenomenon than base metal dissolution at longer holding times. The increased DAZ thickness and the complete isothermal solidification as a result of the improved solid-state diffusion helped increase the uniformity of the hardness profile of the TLP bond at higher holding times (320 and 640 min). The results showed reverse relationship between the athermally solidified zone (ASZ) width and the bonding strength. The highest tensile strength (∼617 MPa) was achieved for the sample bonded at a holding time of 320 min; this strength was more than 80% of the base metal strength. A fractographic analysis of the tensile failure revealed a cellular fracture surface, exhibiting the characteristics of both brittle and ductile fractures. The sites prone to stress concentration and crack initiation were reduced with the completion of isothermal solidification.

35 citations

Journal ArticleDOI
TL;DR: In this article, the effect of bonding time on microstructure and mechanical properties of a transient liquid phase (TLP) bonded Inconel 625 superalloy, using a BNi-2 interlayer, was investigated.

27 citations

Journal ArticleDOI
TL;DR: In this paper, defect-free IN939 superalloy specimens were prepared and characterized using the electron beam selective melting (EBSM) method, and the results showed that the yield strength was influenced by the gradient microstructure.

25 citations

Journal ArticleDOI
TL;DR: In this article, the applicability of transient liquid phase bonding technique to join a nickel-based precipitation-hardened superalloy (Inconel 939) to a solid-solutionhardened one (inconel 625) to avoid the limitations of other joining techniques such as fusion welding was evaluated.

23 citations