Analysis of microstructure and mechanical properties change in laser welding of Ti6Al4V with a multiphysics prediction model

Hong, Kyung-Min; Shin, Yung C.

doi:10.1016/j.jmatprotec.2016.06.034

Cited by 51 publications

(24 citation statements)

References 24 publications

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“…In this sense, the DMLS or SLM process is, in part, similar to laser welding. Hong and Shin in [28] found that when welding the Ti6Al4V alloy, maximum hardness occurs at the fusion zone and HAZ (heat-affected zone) boundaries because of the high cooling rate. In addition, it has been found that the rate of laser welding has an effect on the formation of martensite and, hence, on the resulting hardness.…”

Section: Research Activities Related To Dmls/slm Of Ti6al4vmentioning

confidence: 99%

Influence of Build Orientation, Heat Treatment, and Laser Power on the Hardness of Ti6Al4V Manufactured Using the DMLS Process

Guzanová

Ižaríková

Brezinová

et al. 2017

Metals

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This contribution is focused on the influence of build orientation on hardness of materials sintered using direct metal laser sintering (DMLS) technology. It builds on the current research works that has monitored the influence of build orientation on a fatigue life, mechanical properties, roughness after machining, etc. In the mentioned work, a slight influence of build orientation on the above properties was shown. The hardness was measured on a Ti6Al4V alloy which was made of powder by DMLS technology. The individual materials were sintered at different laser powers, then annealed to remove internal stresses. Part of the experiment examined the metallographic analysis of materials in the direction perpendicular to the sintered layers and parallel with the sintered layers. Microhardness was measured on metallographic cross-sections and the results were statistically processed. The influence of laser power on a respective material hardness was assessed by one-way analysis of variance (ANOVA), a comparison of the hardness between sintered and sintered-annealed samples, as well as the comparison of hardness in the two considered directions was performed by t-test and F-test. A statistically significant difference in the hardness of the materials prepared at different laser powers was found. The influence of heat treatment, as well as the direction of material building also showed a statistically significant difference.

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Section: Research Activities Related To Dmls/slm Of Ti6al4vmentioning

confidence: 99%

Influence of Build Orientation, Heat Treatment, and Laser Power on the Hardness of Ti6Al4V Manufactured Using the DMLS Process

Guzanová

Ižaríková

Brezinová

et al. 2017

Metals

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“…It is accepted practice to visually inspect the surface additively manufactured Ti6Al4V parts for coloration and surface imperfections, as this gives an indication of the effectiveness of the inert gas shielding envelope against atmospheric contamination (Hong and Shin, 2016). In this study, the localized gas shielding is only effective for the most recently deposited layers.…”

Section: Discussionmentioning

confidence: 99%

The effects of forced interpass cooling on the material properties of wire arc additively manufactured Ti6Al4V alloy

Ding

Cuiuri

et al. 2018

Journal of Materials Processing Technology

183

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To achieve improved microstructure and mechanical properties, an innovative wire arc additive manufacturing (WAAM) process with forced interpass cooling using compressed CO 2 was employed in this study to fabricate Ti6Al4V thin-walled structures. The effects of various interpass temperatures and rapid forced cooling on deposition geometry, surface oxidation, microstructural evolution, and mechanical properties of the fabricated part were investigated by laser profilometry, optical microscopy (OM), scanning electron microscopy (SEM), hardness testing and mechanical tensile testing. Results show that the microstructural evolution and mechanical properties of the deposited metal are not greatly affected by an increasing interpass temperature, however, the deposited wall tends to be widened, flattened and exhibit increased surface oxidation through visible coloration. When rapid forced cooling using CO 2 is used between deposited layers, slightly higher hardness values and increased strength can be obtained. This is mainly attributed to the combined effects of less surface oxide and high density dislocation caused by the generation of large amounts of fine-grained acicular α within the microstructure. Furthermore, forced interpass cooling not only improves deposition properties, but also promotes geometrical repeatability and also improved manufacturing efficiency through the reduction of dwell time between deposited layers. ABSTRACTTo achieve improved microstructure and mechanical properties, an innovative wire arc additive manufacturing (WAAM) process with forced interpass cooling using compressed CO 2 was employed in this study to fabricate Ti6Al4V thin-walled structures. The effects of various interpass temperatures and rapid forced cooling on deposition geometry, surface oxidation, microstructural evolution, and mechanical properties of the fabricated part were investigated by laser profilometry, optical microscopy (OM), scanning electron microscopy (SEM), hardness testing and mechanical tensile testing. Results show that the microstructural evolution and mechanical properties of the deposited metal are not greatly affected by an increasing interpass temperature, however, the deposited wall tends to be widened, flattened and exhibit increased surface oxidation through visible coloration. When rapid forced cooling using CO 2 is used between deposited layers, slightly higher hardness values and increased strength can be obtained. This is mainly attributed to the combined effects of less surface oxide and high density dislocation caused by the generation of large amounts of fine-grained acicular α within the microstructure. Furthermore, 2 forced interpass cooling not only improves deposition properties, but also promotes geometrical repeatability and also improved manufacturing efficiency through the reduction of dwell time between deposited layers.

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“…The schematic diagram of the laser scanning path and temperature distribution is shown in Figure 3a. The calculated Ti-V binary phase diagram [22] and continuous cooling diagram of Ti6Al4V [23] are shown in Figure 3b,c, respectively. In the molted zone of the laser-polished layer, two peak temperatures of cycle 1 and 2 were in excess of liquidus temperature TL, as displayed in Figure 3a.…”

Section: Thermal Analysismentioning

confidence: 99%

Material Characterization, Thermal Analysis, and Mechanical Performance of a Laser-Polished Ti Alloy Prepared by Selective Laser Melting

Wang

et al. 2019

Metals

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The laser polishing technique offers an adaptable, accurate, and environmentally friendly solution to enhance the surface quality of additive manufactured metallic components. Recent work has shown that the surface roughness of laser additive manufactured metallic alloys can be significantly reduced via the laser polishing method. This paper examines the mechanical performances of a laser polished surface fabricated by selective laser melting (SLM). Compared with the original SLM surface, systematic measurements revealed that the surface roughness of the laser polished surface can be effectively reduced from 6.53 μm to 0.32 μm, while the microhardness and wear resistance increased by 25% and 39%, respectively. Through a thermal history analysis of the laser polishing process using the finite element model, new martensitic phase formation in the laser polished layer is carefully explained, which reveals significant effects on residual stress, strength, and fatigue. These findings establish foundational data to predict the mechanical performance of laser polished metallic components fabricated by additive manufacturing methods, and pave the way for functional surface design with practical application via the laser process.

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Analysis of microstructure and mechanical properties change in laser welding of Ti6Al4V with a multiphysics prediction model

Cited by 51 publications

References 24 publications

Influence of Build Orientation, Heat Treatment, and Laser Power on the Hardness of Ti6Al4V Manufactured Using the DMLS Process

Influence of Build Orientation, Heat Treatment, and Laser Power on the Hardness of Ti6Al4V Manufactured Using the DMLS Process

The effects of forced interpass cooling on the material properties of wire arc additively manufactured Ti6Al4V alloy

Material Characterization, Thermal Analysis, and Mechanical Performance of a Laser-Polished Ti Alloy Prepared by Selective Laser Melting

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