Microstructure and mechanical properties of selective laser melted Ti6Al4V alloy

Losertová, Monika; Kubeš, V.

doi:10.1088/1757-899x/266/1/012009

Cited by 24 publications

(18 citation statements)

References 7 publications

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“…The microstructural observations for stress relieved samples revealed a basketweave structure typical for L-PBF processed Ti-6Al-4 V. It is assumed to be α′-martensite formed inside the prior-β grains [11]. A hardness of around 390 HV10 indicates α′-martensite whereas HIPed samples have a Vickers hardness of around 335 HV10 increasing with the build chamber oxygen concentration [38,39]. HIPed samples do have a certain amount of β-phase reducing the hardness and tensile strength whilst increasing ductility.…”

Section: Discussionmentioning

confidence: 99%

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The influence of oxygen on the chemical composition and mechanical properties of Ti-6Al-4V during laser powder bed fusion (L-PBF)

Dietrich

Diller

Goff

et al. 2020

Additive Manufacturing

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In Laser powder bed fusion (L-PBF), metal powders, sensitive to humidity and oxygen, like AlSi10Mg or Ti-6Al-4 V are used as starting material. Titanium-based materials are influenced by oxygen and nitrogen due to the formation of oxides and nitrides, respectively. During this research, the oxygen concentration in the build chamber was controlled from 2 ppm to 1000 ppm using an external measurement device. Built Ti-6Al-4 V specimens were evaluated regarding their microstructure, hardness, tensile strength, notch toughness, chemical composition and porosity, demonstrating the importance of a stable atmospheric control. It could be shown that an increased oxygen concentration in the shielding gas atmosphere leads to an increase of the ultimate tensile strength by 30 MPa and an increased (188.3 ppm) oxygen concentration in the bulk material. These results were compared to hot isostatic pressed (HIPed) samples to prevent the influence of porosity. In addition, the fatigue behavior was investigated, revealing increasingly resistant samples when oxygen levels in the atmosphere are lower.

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Section: Discussionmentioning

confidence: 99%

“…Due to the HIP process, the microstructure consists of αand βphase. The α-phase is depicted in brighter colors whereas the β-phase is darker [39].…”

Section: Microstructurementioning

confidence: 99%

The influence of oxygen on the chemical composition and mechanical properties of Ti-6Al-4V during laser powder bed fusion (L-PBF)

Dietrich

Diller

Goff

et al. 2020

Additive Manufacturing

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“…Taking a step further by incorporating MBAs such as Cu would enable the production of biomimetic implants with antibacterial properties, which would enhance the longevity of orthopaedic implants and sustain the improved quality of life of implant patients. Preliminary investigations of in situ alloying (incorporating) Cu into Ti-based precursor powder for manufacturing biomedical devices using LPBF technology have been conducted [78,79]. The authors based the composition of the alloy (amount of Cu) on what was already known from the conventional methods of manufacturing (<5 wt.% Cu).…”

Section: Metal Additive Manufacturingmentioning

confidence: 99%

Additive Manufacturing of Titanium-Based Implants with Metal-Based Antimicrobial Agents

Dzogbewu

Preez

2021

Metals

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Due to increasing bacterial resistance to antibiotics, surface coatings of medical devices with antimicrobial agents have come to the fore. These surface coatings on medical devices were basically thin coatings that delaminated from the medical devices due to the fluid environment and the biomechanical activities associated with in-service implants. The conventional methods of manufacturing have been used to alloy metal-based antimicrobial (MBA) agents such as Cu with Ti6Al4V to enhance its antibacterial properties but failed to produce intricate shapes. Additive manufacturing technology, such as laser powder bed fusion (LPBF), could be used to produce the Ti6Al4V–xCu alloy with intricate shapes to enhance osseointegration, but have not been successful for texturing the surfaces of the Ti6Al4V–xCu samples at the nanoscale.

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“…L-PBF manufactured components suffer from thermal residual stress [9] and annealing was carried out to relieve the stress [10]. AB cubes and cylinders form L-PBF and SM-L-PBF builds were heat-treated in a vacuum furnace at 1048 ± 10°C for 60 min, with a heating rate of 9°C/min under 1 × 10 -4 mbar to 1 × 10 -6 mbar.…”

Section: Heat Treatmentmentioning

confidence: 99%

Multi-Laser Powder Bed Fusion Benchmarking—Initial Trials with Inconel 625

Wong

Dawson

Ravi

et al. 2019

Int J Adv Manuf Technol

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Production rate is an increasingly important factor in the deployment of metal additive manufacturing (AM) throughout industry. To address the perceived low production rate of metal AM systems based on single-laser powder bed fusion (L-PBF), several companies now offer systems in which melting has been parallelised by the introduction of multiple, independently controlled laser beams. Nevertheless, a full set of studies is yet to be conducted to benchmark the efficiency of multi-laser systems and, at the same time, to verify if the mechanical properties of components are compromised due to the increase in build rate. This study addresses the described technology gaps and presents a 4-beam L-PBF system operating in "single multi" (SM) mode (SM-L-PBF) where each of the four lasers is controlled so that it melts all of a particular components' layers and produces specimens for comparison with standard L-PBF specimens from the same machine. That is all four lasers making all of some of the parts were compared to a single-laser manufacturing all of the parts. Build parameters were kept constant throughout the manufacturing process and the material used was Inconel 625 (IN625). Stress-relieving heat treatment was conducted on As-built (AB) specimens. Both AB and heat-treated (HT) specimen sets were tested for density, microstructure, tensile strength and hardness. Results indicate that the stress-relieving heat treatment increases specimen ductility without compromising other mechanical properties. SM-L-PBF has achieved a build rate of 14 cm 3 /h when four 200 W lasers were used to process IN625 at a layer thickness of 30 μm. An increase in the build rate of 2.74 times (build time reduction: 63%) has been demonstrated when compared to that of L-PBF, with little to no compromises in specimen mechanical properties. The observed tensile properties exceed the American Society for Testing Materials (ASTM) requirements for IN625 (by a margin of 22 to 26% in the 0.2% offset yield strength). Average specimen hardness and grain size are in the same order as that reported in literatures. The study has demonstrated that a multi-laser AM system opens up opportunities to tackle the impasse of low build rate in L-PBF in an industrial setting and that at least when operating in single mode there is no detectable degradation in the mechanical and crystallographic characteristics of the components produced.

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Microstructure and mechanical properties of selective laser melted Ti6Al4V alloy

Cited by 24 publications

References 7 publications

The influence of oxygen on the chemical composition and mechanical properties of Ti-6Al-4V during laser powder bed fusion (L-PBF)

The influence of oxygen on the chemical composition and mechanical properties of Ti-6Al-4V during laser powder bed fusion (L-PBF)

Additive Manufacturing of Titanium-Based Implants with Metal-Based Antimicrobial Agents

Multi-Laser Powder Bed Fusion Benchmarking—Initial Trials with Inconel 625

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