Selective laser melting of Ti6Al4V: Effect of laser re-melting

Karimi, J.; Suryanarayana, C.; Okulov, Ilya; Prashanth, Konda Gokuldoss

doi:10.1016/j.msea.2020.140558

Cited by 80 publications

(18 citation statements)

References 56 publications

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“…These martensite lamellae, having widths of~2 microns, result from the rapid cooling associated with the laser beam processing. The corresponding HRC hardness average characteristic of the test components represented in Figure 8 was 44.6, which along with the martensitic microstructure in Figure 8b,c is typical for LPBF as-built Ti-6Al-4V alloy components utilizing spherical, atomized precursor powder [2,[7][8][9]17]. The alpha-prime (martensite) microstructure shown in Figure 8b,c results from the diffusionless, composition invariant beta → alpha-prime martensite transformation, and was also observed by Jaber et al [12] using an HDH-non-spherical/spherical Ti-6Al-4V powder mixture for laser beam powder-bed fusion processing, as well as the more recent work of Narra et al [16] using a modified, non-spherical HDH Ti-6Al-4V alloy precursor powder.…”

Section: Microstructure Analysis and Discussionmentioning

confidence: 85%

Investigation of Microstructure and Mechanical Properties for Ti-6Al-4V Alloy Parts Produced Using Non-Spherical Precursor Powder by Laser Powder Bed Fusion

Varela

Arrieta

Paliwal³

et al. 2021

Materials

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An unmodified, non-spherical, hydride-dehydride (HDH) Ti-6Al-4V powder having a substantial economic advantage over spherical, atomized Ti-6Al-4V alloy powder was used to fabricate a range of test components and aerospace-related products utilizing laser beam powder-bed fusion processing. The as-built products, utilizing optimized processing parameters, had a Rockwell-C scale (HRC) hardness of 44.6. Following heat treatments which included annealing at 704 °C, HIP at ~926 °C (average), and HIP + anneal, the HRC hardnesses were observed to be 43.9, 40.7, and 40.4, respectively. The corresponding tensile yield stress, UTS, and elongation for these heat treatments averaged 1.19 GPa, 1.22 GPa, 8.7%; 1.03 GPa, 1.08 GPa, 16.7%; 1.04 GPa, 1.09 GPa, 16.1%, respectively. The HIP yield strength and elongation of 1.03 GPa and 16.7% are comparable to the best commercial, wrought Ti-6Al-4V products. The corresponding HIP component microstructures consisted of elongated small grains (~125 microns diameter) containing fine, alpha/beta lamellae.

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Section: Microstructure Analysis and Discussionmentioning

confidence: 85%

Investigation of Microstructure and Mechanical Properties for Ti-6Al-4V Alloy Parts Produced Using Non-Spherical Precursor Powder by Laser Powder Bed Fusion

Varela

Arrieta

Paliwal³

et al. 2021

Materials

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“…In-situ Laser Directed Energy Deposition allows for the obtaining of titanium alloys with low elastic modulus, excellent corrosion resistance, and outstanding in vitro cytocompatibility. Particularly, the laserdeposited Ti-35Zr-25Nb alloy has an elastic modulus 34% lower than that of cp-Ti grade 2 (E = 106.8 ± 2.4 GPa), and is 36-39% lower than that of the Ti-6Al-4V alloy [1,56,57], the most used in applications in traumatology and orthopedics. Ti-35Zr-25Nb alloy has very good properties in order to avoid stress shielding problems.…”

Section: Methodsmentioning

confidence: 98%

In-Situ Laser Directed Energy Deposition of Biomedical Ti-Nb and Ti-Zr-Nb Alloys from Elemental Powders

González

Contreras

Punset

et al. 2021

Metals

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In order to achieve the required properties of titanium implants, more resources and research are needed to turn into reality the dream of developing the perfect implant material. The objective of this study was to evaluate the viability of the Laser Directed Energy Deposition to produce biomedical Ti-Nb and Ti-Zr-Nb alloys from elemental powders (Ti, Nb and Zr). The Laser Directed Energy Deposition is an additive manufacturing process used to build a component by delivering energy and material simultaneously. The material is supplied in the form of particles or wire and a laser beam is employed to melt material that is selectively deposited on a specified surface, where it solidifies. Samples with different compositions are characterized to analyze their morphology, microstructure, constituent phases, mechanical properties, corrosion resistance and cytocompatibility. Laser-deposited Ti-Nb and Ti-Zr-Nb alloys show no relevant defects, such as pores or cracks. Titanium alloys with lower elastic modulus and a significantly higher hardness than Ti grade 2 were generated, therefore a better wear resistance could be expected from them. Moreover, their corrosion resistance is excellent due to the formation of a stable passive protective oxide film on the surface of the material; in addition, they also possess outstanding cytocompatibility.

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“…However, LPBF metals are very sensitive to a number of process parameters and conditions, resulting in a great variation of possible mechanical properties depending on process setup. The understanding of influence of numerous build parameters is key to achieving the best properties, e.g., steels with high strength and ductility [ 1 , 2 , 3 ]. To characterize the anisotropy of mechanical properties of produced material, many studies use the analysis of specimens, built in different orientations [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Anisotropy of Mechanical Properties and Residual Stress in Additively Manufactured 316L Specimens

et al. 2021

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In the presented study, LPBF 316L stainless steel tensile specimens were manufactured in three different orientations for the analysis of anisotropy. The first set of specimens was built vertically on the build platform, and two other sets were oriented horizontally perpendicular to each other. Tensile test results show that mean Young’s modulus of vertically built specimens is significantly less then horizontal ones (158.7 GPa versus 198 GPa), as well as yield strength and elongation. A role of residual stress in a deviation of tensile loading diagrams is investigated as a possible explanation. Simulation of the build process on the basis of ABAQUS FEA software was used to predict residual stress in 316L cylindrical specimens. Virtual tensile test results show that residual stress affects the initial stage of the loading curve with a tendency to reduce apparent Young’s modulus, measured according to standard mechanical test methods.

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Selective laser melting of Ti6Al4V: Effect of laser re-melting

Cited by 80 publications

References 56 publications

Investigation of Microstructure and Mechanical Properties for Ti-6Al-4V Alloy Parts Produced Using Non-Spherical Precursor Powder by Laser Powder Bed Fusion

Investigation of Microstructure and Mechanical Properties for Ti-6Al-4V Alloy Parts Produced Using Non-Spherical Precursor Powder by Laser Powder Bed Fusion

In-Situ Laser Directed Energy Deposition of Biomedical Ti-Nb and Ti-Zr-Nb Alloys from Elemental Powders

Anisotropy of Mechanical Properties and Residual Stress in Additively Manufactured 316L Specimens

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