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15 pages, 6539 KiB

Open AccessArticle

Effect of Inconel 718 Filler on the Microstructure and Mechanical Properties of Inconel 690 Joint by Ultrasonic Frequency Pulse Assisted TIG Welding

by Ke Han, Xin Hu, Xinyue Zhang, Hao Chen, Jinping Liu, Xiaodong Zhang, Peng Chen, Hongliang Li, Yucheng Lei and Jinhui Xi

Materials 2024, 17(12), 2857; https://doi.org/10.3390/ma17122857 - 11 Jun 2024

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Abstract

Ultrasonic frequency pulse assisted TIG welding (UFP-TIG) experiments were conducted to join Inconel 690 alloy (IN690) by adding Inconel 718 alloy (IN718) as the filler. The effect of the filler on the microstructure, mechanical properties, and ductility dip cracking (DDC) susceptibility of IN690 [...] Read more.

Ultrasonic frequency pulse assisted TIG welding (UFP-TIG) experiments were conducted to join Inconel 690 alloy (IN690) by adding Inconel 718 alloy (IN718) as the filler. The effect of the filler on the microstructure, mechanical properties, and ductility dip cracking (DDC) susceptibility of IN690 joints were investigated. The results show that a variety of precipitates, including MC-type carbide and Laves phases, are formed in the weld zone (WZ), which are uniformly dispersed in the interdendritic region and grain boundaries (GBs). The increase in the thickness of the IN718 filler facilitates the precipitation and growth of Laves phases and MC carbides. However, the formation of Laves phases in the WZ exhibits a lower bonding force with the matrix and deteriorates the tensile strength of IN690 joints. Due to the moderate content of Laves phases in the WZ, the IN690 joint with 1.0 mm filler reaches the maximum tensile strength (627 MPa), which is about 96.5% of that of the base metal (BM). The joint with 1.0 mm filler also achieves the highest elongation (35.4%). In addition, the strain-to-fracture tests indicate that the total length of cracks in the joint with the IN718 filler decreases by 66.49% under a 3.8% strain. As a result, the addition of the IN718 filler significantly improves the mechanical properties and DDC resistance of IN690 joints. Full article

(This article belongs to the Special Issue Advanced Welding Technologies and Additive Manufacturing of Alloys and Metals (2nd Edition))

12 pages, 35525 KiB

Open AccessArticle

AZ91 Magnesium Alloy CMT Cladding Layer Processed Using Friction Stir Processing: Effect of Traverse Speed on Microstructure and Mechanical Properties

by Huichao Zhao, Junqi Shen, Shengsun Hu, Yahui Zhen and Yang Chen

Materials 2024, 17(10), 2348; https://doi.org/10.3390/ma17102348 - 15 May 2024

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Abstract

Friction stir processing (FSP) is a solid-state treating method to enhance the mechanical properties of materials by altering their microstructure. In this study, FSP was applied to the AZ91 magnesium alloy cladding layer prepared using cold metal transition (CMT) technology, and the purpose [...] Read more.

Friction stir processing (FSP) is a solid-state treating method to enhance the mechanical properties of materials by altering their microstructure. In this study, FSP was applied to the AZ91 magnesium alloy cladding layer prepared using cold metal transition (CMT) technology, and the purpose was to investigate the effect of the traverse speed of the H13 steel stirring head under a constant rotation speed on the microstructure and mechanical properties of the cladding layer. The results demonstrated that FSP could effectively decrease the grain size of the cladding layer and lead to the dispersion and dissolution of the coarse β-Mg₁₇Al₁₂ second phase into the α-Mg matrix. The mechanical characteristics of the processed cladding layer were significantly enhanced compared to the unprocessed cladding layer due to the grain refinement and second-phase strengthening induced by FSP. When the stirring head rotation speed was set at 300 r/min, the average microhardness and tensile properties of the specimens showed a tendency of initially increasing and then dropping as the traverse speed increased. The cladding layer, obtained at a traverse speed of 60 mm/min, displayed optimal mechanical properties with an average microhardness, tensile strength, and elongation of 85.6 HV_0.1, 278.5 MPa, and 13.4%, respectively. Full article

(This article belongs to the Special Issue Advanced Welding Technologies and Additive Manufacturing of Alloys and Metals (2nd Edition))

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12 pages, 6444 KiB

Open AccessCommunication

Effect of Welding Gap of Thin Plate Butt Welds on Inherent Strain and Welding Deformation of a Large Complex Box Structure

by Liping Zhang, Genchen Peng, Fan Yang, Zhengyu Meng, Xiaoming Yuan, Yangyang Fan, Wen Li and Lijie Zhang

Materials 2024, 17(9), 1934; https://doi.org/10.3390/ma17091934 - 23 Apr 2024

Viewed by 567

Abstract

In this study, an effective numerical model was developed for the calculation of the deformation of laser-welded 3 mm 304L stainless steel plates with different gaps (0.2 mm, 0.5 mm, and 1.0 mm). The welding deformation would become larger when the welding gaps [...] Read more.

In this study, an effective numerical model was developed for the calculation of the deformation of laser-welded 3 mm 304L stainless steel plates with different gaps (0.2 mm, 0.5 mm, and 1.0 mm). The welding deformation would become larger when the welding gaps increased, and the largest deformation values along the Z direction, of 4 mm, were produced when the gap value was 1.0 mm. A larger plastic strain region was generated in the location near the weld seam, since higher plastic deformation had occurred. In addition, the tensile stress model was also applied at the plastic strain zone and demonstrated that a larger welding gap led to a wider residual stress area. Based on the above results, inherent deformations for butt and corner joints were calculated according to inherent strain theory, and the welding formation for the complex structure was calculated with different gaps. The numerical results demonstrated that a larger deformation was also produced with a larger welding gap and that it could reach the highest value of 10.1 mm. This proves that a smaller welding gap should be adopted during the laser welding of complex structures to avoid excessive welding deformation. Full article

(This article belongs to the Special Issue Advanced Welding Technologies and Additive Manufacturing of Alloys and Metals (2nd Edition))

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