Metallographic investigation of laser-treated ductile iron surface with different laser heat inputs

Al-Sayed, Samar Reda; Elgazzar, Haytham; Nofal, Adel

doi:10.1016/j.asej.2023.102189

Cited by 5 publications

(4 citation statements)

References 31 publications

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“…Low values of J thermal correspond to overall low thermal gradients in the substrate, i.e., the build part, which results in fewer undesirable effects such as residual stresses, deformations, and reduced mechanical properties [7,8]. The second component of the fitness function evaluates the properties of the particular LB path solutions with respect to the AM process features and constraints.…”

Section: Fitness Functionmentioning

confidence: 99%

“…Therefore, one of the key challenges in laser-based AM revolves around controlling temperature distribution in the fabricated part during the deposition process. The laser-induced heat input can lead to nonuniform temperature distributions within the built part, resulting in undesirable effects such as residual stresses, deformations, and reduced mechanical properties of the final 3D-printed part [7,8]. To illustrate this effect, a simple experimental demonstration, formulated as an experimental motivation for this research, is provided in the next section.…”

Section: Introductionmentioning

confidence: 99%

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Genetic Algorithm-Based Framework for Optimization of Laser Beam Path in Additive Manufacturing

Potočnik,

Jeromen,

Govekar

2024

Metals

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In this study, a genetic algorithm-based laser beam (LB) path optimization method is presented to improve laser-based additive manufacturing (LBAM). To emulate the LBAM process, LB irradiation of a thin metal substrate is applied. The LB path generation is formulated as the search for the optimal sequence of LB irradiation into the cells on the substrate that minimizes the fitness function, which is composed of two components, i.e., thermal fitness and process fitness. The thermal fitness is expressed by the average thermal gradient, and a simple thermal model is developed to simulate the effects of laser-induced heat input on the temperature distribution in the substrate. The process fitness regulates the suitability of the proposed LB path for the implementation of the LBAM process. In addition to standardized tool paths (i.e., raster, spiral, etc.), novel LB path generators are proposed to define the initial population of LB path solutions. To implement a genetic algorithm-based LB path optimization, a framework is proposed, and custom initialization, crossover, and mutation operators are developed for application in LBAM. The effectiveness of the proposed approach is demonstrated through a simulation case study aiming to identify LB paths that minimize the fitness function and thus provide more suitable LB path solutions with respect to the defined fitness function. Compared with the traditional trial-and-error LB path formulations, the proposed approach provides an improved and automated method for an efficient laser beam path selection in LBAM.

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Section: Fitness Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Genetic Algorithm-Based Framework for Optimization of Laser Beam Path in Additive Manufacturing

Potočnik,

Jeromen,

Govekar

2024

Metals

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“…Chen et al [ 33 ] found that the hardness of the laser-quenched specimens increased about 3-fold, the wear depth decreased by about 35%, and the wear mechanism changed from plowing wear to adhesive wear. The results of Samar et al [ 34 ] showed that the microstructure of ductile iron after laser quenching consisted of acicular martensite, austenite, and graphite, and that the hardness was increased nearly 6-fold compared to the base metal.…”

Section: Introductionmentioning

confidence: 99%

Improving the Properties of Gray Cast Iron by Laser Surface Modification

et al. 2023

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Laser surface modification is a widely used technology to improve the properties of functional surfaces. In this study, the properties of gray cast iron are modified by laser surface modification, and the influence of laser quenching on the properties of cast iron in terms of frictional vibration and noise, friction and wear, internal structure, residual stress, hardness, and corrosion resistance is investigated. The experimental results show that, after high-power laser quenching, the frictional vibrations and noise of most gray cast iron specimens are decreased, but the coefficients of friction against a bearing steel counterface are increased and more stable. The surface and sub-surface hardness of all laser-quenched cast iron specimens is significantly increased. The residual stresses on the surface of the cast iron specimens are significantly increased and changed from tensile to compressive residual stresses. Experimental modal testing results show that the modal damping ratios of the laser-treated specimens are increased significantly, although their modal frequencies are not significantly changed. In addition, through the metallographic observation, XRD (X-ray diffraction) analysis, and TEM (transmission electron microscopy) observation, it is found that the microstructures of the cast iron specimen after high-power laser modification become fine-grained, and the pearlite and ferrite in the matrix become fine martensite, which leads to the improvement of the dynamical, tribological, and chemical properties of cast iron after laser modification.

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“…At present, many effective surface modification methods have been developed. In addition to traditional surface modification technologies such as shot peening, surface quenching, chemical heat treatment, etc., high-energy beam surface modification technologies containing a laser beam [1], electron beam [2] and plasma beam [3] have been widely used in the past decades. Among them, the plasma transferred arc (PTA) has many advantages of minimal thermal deformations, metallurgical bonding and refined grains under rapid cooling.…”

Section: Introductionmentioning

confidence: 99%

Effect of Scanning Strategy on the Microstructure and Triboperformance of FeNiCrMo Coating Manufactured by Plasma Transferred Arc

Xiao,

Li,

Song

et al. 2023

Materials

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To increase the coating thickness and service life of the FeNiCrMo coating, a plasma transferred arc (PTA) double-track alloying technique was employed to enhance the surface triboperformance of the ductile iron. Optical microscopy (OM), X-ray diffraction (XRD), electron probe X-ray microanalyzer (EPMA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Vickers hardness tester, and tribological tester were subsequently used to evaluate the effect of the double alloying treatment tracks on the microstructure and triboperformance of the coating. The results indicate that the content of the cementite in the sample with a double-track treatment increases 3.90 wt.% and the content of the martensite decreases 13.04 wt.% compared with the sample with a single-track treatment, which results in the maximum microhardness of the sample fabricated by double track increasing from 837 ± 10 HV0.2 for the sample fabricated by single track to 871 ± 7 HV0.2. Thus, the wear rate is lower than that of the sample with a single-track treatment. In addition, the distribution of alloying elements is more uniform and coating thickness is higher in the double track than those of the single-track-treated one. Therefore, the double-track PTA alloying treatment is favored for hardfacing ductile iron with a FeNiCrMo alloy coating due to its enhanced triboperformance and longer service life.

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Metallographic investigation of laser-treated ductile iron surface with different laser heat inputs

Cited by 5 publications

References 31 publications

Genetic Algorithm-Based Framework for Optimization of Laser Beam Path in Additive Manufacturing

Genetic Algorithm-Based Framework for Optimization of Laser Beam Path in Additive Manufacturing

Improving the Properties of Gray Cast Iron by Laser Surface Modification

Effect of Scanning Strategy on the Microstructure and Triboperformance of FeNiCrMo Coating Manufactured by Plasma Transferred Arc

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