Surface layer properties of ultrasonic impact–treated AA7075 aluminum alloy

Kahraman, Fatih

doi:10.1177/0954405416685386

Cited by 13 publications

(3 citation statements)

References 31 publications

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“…Based on the results presented in Figure 15(c), grain refinement occurs at the shot-peened HAZ because grains under deformation are stressed and divided into smaller sizes, which corresponds with the conclusion of Kahraman et al 30 The grain size of the unaffected base material was determined to be 63.639 µm. However, the grain size of the shot-peened HAZ was determined to be 55.56 µm, which is much finer compared to the base material.…”

Section: Resultssupporting

confidence: 72%

Numerical simulation of post-weld shot peening using combined discrete and finite element methods (DEM-FEM)

Ahmad

Gong

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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The numerical simulation of the post-weld shot peening (SP) process was performed to analyze the influence of various SP parameters on the final induced compressive residual stress (CRS). Firstly, the welding process was simulated based on the Finite Element Method (FEM) using ABAQUS CAE and FORTRAN user subroutine code, from which the initial welding-induced tensile residual stresses (TRS) were obtained. The FE model was validated using the results obtained from the TIG welding of the aluminum 2219 alloy (AA 2219) plate. Then, the post-weld SP process was numerically simulated using the combined discrete and finite element methods (DEM-FEM). The computed CRS from the simulation was compared with the experimentally measured outcome to validate the DEM-FEM model, and good agreement was observed from the compared results. Finally, the post-weld SP model was applied to extensively analyze the influence of the various SP parameters related to the peening media and target material on the final CRS.

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Section: Resultssupporting

confidence: 72%

Numerical simulation of post-weld shot peening using combined discrete and finite element methods (DEM-FEM)

Ahmad

Gong

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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“…Moreover, the thickness of the PDL of the welded joint after A–DSUIT was smaller than that DSUIT due to the improvement of the joint microhardness after aging. No phase transformation occurred in the welded joint after DSUIT, which only refined the grain diameter on the joint’s surface [ 26 ].…”

Section: Resultsmentioning

confidence: 99%

Improving the Properties of Laser-Welded Al–Zn–Mg–Cu Alloy Joints by Aging and Double-Sided Ultrasonic Impact Compound Treatment

Chen¹,

Liu²

2021

Materials

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To improve the loose structure and serious porosity of (Al–Zn–Mg–Cu) 7075 aluminum alloy laser-welded joints, aging treatment, double-sided ultrasonic impact treatment (DSUIT), and a combination of aging and DSUIT (A–DSUIT) were used to treat joints. In this experiment, the mechanism of A–DSUIT on the microstructure and properties of welded joints was analyzed. The microstructure of the welded joints was observed using optical microscopy, scanning electron microscopy, and electron backscatter diffraction (EBSD). The hardness and tensile properties of the welded components under the different processes were examined via Vickers hardness test and a universal tensile testing machine. The results showed that, after the aging treatment, the dendritic structure of the welded joints transformed into an equiaxed crystal structure. Moreover, the residual tensile stress generated in the welding process was weakened, and the hardness and tensile strength were significantly improved. After DSUIT, a plastic deformation layer of a certain thickness was generated from the surface downward, and the residual compressive stress was introduced to a certain depth of the joint. However, the weld zone unaffected by DSUIT still exhibited residual tensile stress. The inner microhardness of the joint surface improved; the impact surface hardness was the largest and gradually decreased inward to the weld zone base metal hardness, with a small improvement in the tensile strength. Compared with the single treatment process, the microstructural and mechanical properties of the welded joint after A–DSUIT were comprehensively improved. The microhardness and tensile strength of the welded joint reached 200 HV and 615 MPa, respectively, for an increase of 45.8% and 61.8%, respectively. Observation of the fractures of the tensile specimens under the different treatment processes showed that the fractures before the aging treatment were mainly ductile fractures while those after were mainly brittle fractures. After DSUIT of the welded joints, a clear and dense plastic deformation layer was observed in the fracture of the tensile specimens and effectively improved the tensile properties of the welded joints. Under the EBSD characterization, the larger the residual compressive stress near the ultrasonic impact surface, the smaller the grain diameter and misorientation angle, and the lower the texture strength. Finally, after A–DSUIT, the hardness and tensile properties improved the most.

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“…The surface of the specimen after ultrasonic impact treatment (UIT) will form a gradient deformation layer of certain depth, including surface amorphous and ultrafine crystals [ 6 ]. Gradient nanostructured metallic materials have surface grain sizes in the nanometer range, with internal grain sizes gradually increasing to the micrometer range.…”

Section: Introductionmentioning

confidence: 99%

Effect of ultrasonic surface impact on the microstructural characterization and mechanical properties of 316L austenitic stainless steel

Zhu,

Zhuang,

et al. 2024

PLoS ONE

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In the present study, effect of ultrasonic impact treatment (UIT) on the microstructural characterization and mechanical properties of 316L stainless steel (hereinafter referred to as 316L) was investigated experimentally. The fatigue fracture mechanism of 316L before and after UIT was revealed. The experimental results indicated that the martensitic grain size induced at the impact edge was about 2.00 Å. The surface modified 316L formed a gradient nanostructure and induced a martensitic phase transformation. The hardness of the surface layer of the modified 316L was twice the hardness of its matrix. The tensile strengths of 316L before and after UIT were 576 MPa and 703 MPa, respectively. The stretching stripes of 316L were more disordered after UIT. The fatigue strengths of 316L before and after UIT were 267 MPa and 327 MPa, respectively. The fatigue cracking of 316L started from the austenite grain boundaries. The fatigue fracture surface was relatively rough. The fatigue crack sources of the modified 316L came from internal inclusions. The inclusions were oxides dominated by SiO2. As the stress range increased, the crack initiation site migrated to the interior and the fatigue fracture surface became flatter.

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Surface layer properties of ultrasonic impact–treated AA7075 aluminum alloy

Cited by 13 publications

References 31 publications

Numerical simulation of post-weld shot peening using combined discrete and finite element methods (DEM-FEM)

Numerical simulation of post-weld shot peening using combined discrete and finite element methods (DEM-FEM)

Improving the Properties of Laser-Welded Al–Zn–Mg–Cu Alloy Joints by Aging and Double-Sided Ultrasonic Impact Compound Treatment

Effect of ultrasonic surface impact on the microstructural characterization and mechanical properties of 316L austenitic stainless steel

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