A Review on Additive Manufacturing of Titanium Alloys for Aerospace Applications: Directed Energy Deposition and Beyond Ti-6Al-4V

Liu, Zhiying; He, Bei; Lyu, Tianyi; Zou, Yu

doi:10.1007/s11837-021-04670-6

Cited by 174 publications

(47 citation statements)

References 88 publications

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“…Titanium is known as a strategic metal and also as the "third metal" [1,2]. Titanium sponge and titanium dioxide chloride are key strategic materials that support the development of modern society [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

The Conversion of Calcium-Containing Phases and Their Separation with NaCl in Molten Salt Chlorinated Slags at High Temperature

Chen

Liu²,

Wen

et al. 2021

Sustainability

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The titanium resources in Panxi reign, China, have a high-impurities content of Ca and Mg, which is usually processed by the molten salt chlorination process. This process allows higher Ca and Mg content in its furnace burdens. However, there is a huge amount of molten salt chlorinated slag produced by this process, consisting of complex compounds and waste NaCl/KCl salts. These slags are always stockpiled without efficient utilization, causing serious environmental pollutions. To recycle the NaCl in the slag back to the molten salt chlorination process, a novel process to deal with those molten salt chlorinated slags with phase conversion at high temperature is presented in this paper. The calcium-containing solid phase was generated when Na2SiO3 was added to the molten salt chlorinated slags at high temperature, while NaCl was kept as a liquid. Thus, liquid NaCl was easily separated from the calcium-containing solid phase, and it could be reused in the molten salt chlorination process. The conversion of calcium-containing phases and their separation of NaCl are the key parts of this work, and they have been systematically studied in this paper; thermodynamic analysis, phase transformation behavior, and calcium removal behavior have all been investigated. The calcium removal rate is 78.69% when the molar ratio of CaCl2:Na2SiO3 is 1:1.5 at 1173 K and N2 atmosphere.

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Section: Introductionmentioning

confidence: 99%

The Conversion of Calcium-Containing Phases and Their Separation with NaCl in Molten Salt Chlorinated Slags at High Temperature

Chen

Liu²,

Wen

et al. 2021

Sustainability

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“…Product of powder density ρ and melt pool volume is the mass of powder in the ellipsoidal melt pool. The specific internal energy e t is measured with respect to ambient temperature, as shown in Equation (2).…”

Section: Energy Balance Of Melt Pool Volumementioning

confidence: 99%

“…Product of powder density ρ and melt pool volume V(t) is the mass of powder in the ellipsoidal melt pool. The specific internal energy e(t) is measured with respect to ambient temperature, T a as shown in Equation (2). T m is melting temperature and c s and c l are the specific heat capacity of solid and liquid states, while h SL is the latent heat of fusion.…”

Section: Energy Balance Of Melt Pool Volumementioning

confidence: 99%

“…There are many metal-based AM processes, but laser powder bed fusion (LPBF) imparts better density, strength, and geometric tolerance. Parts produced by the LPBF process are used in aerospace [1,2] and medical implants [3,4]. In LPBF, parts can be built using one of two techniques: selective laser melting (SLM) and electron beam melting (EBM) [5].…”

Section: Introductionmentioning

confidence: 99%

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Feedback Control of Melt Pool Area in Selective Laser Melting Additive Manufacturing Process

et al. 2021

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Selective laser melting (SLM), a metal powder fusion additive manufacturing process, has the potential to manufacture complex components for aerospace and biomedical implants. Large-scale adaptation of these technologies is hampered due to the presence of defects such as porosity and part distortion. Nonuniform melt pool size is a major cause of these defects. The melt pool size changes due to heat from the previous powder bed tracks. In this work, the effect of heat sourced from neighbouring tracks was modelled and feedback control was designed. The objective of control is to regulate the melt pool cross-sectional area rejecting the effect of heat from neighbouring tracks within a layer of the powder bed. The SLM process’s thermal model was developed using the energy balance of lumped melt pool volume. The disturbing heat from neighbouring tracks was modelled as the initial temperature of the melt pool. Combining the thermal model with disturbance model resulted in a nonlinear model describing melt pool evolution. The PID, a classical feedback control approach, was used to minimize the effect of intertrack disturbance on the melt pool area. The controller was tuned for the desired melt pool area in a known environment. Simulation results revealed that the proposed controller regulated the desired melt pool area during the scan of multiple tracks of a powder layer within 16 milliseconds and within a length of 0.04 mm reducing laser power by 10% approximately in five tracks. This reduced the chance of pore formation. Hence, it enhances the quality of components manufactured using the SLM process, reducing defects.

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“…Metallic materials for aerospace applications must be characterized by high mechanical strength, toughness and corrosion resistance at high and low temperatures [1][2][3][4]. Commercially, pure titanium and its alloys are widely used in this application field; 155,000 kg of these materials were used in 2020 alone [5]) as inter-tank structures (also in the cryogenic stage of launch vehicles), cockpit window frames, wing boxes, fasteners, turbo engine parts, and for the aircraft fuselage, thanks to their low density (~−60% of steel) [2,6,7]. In addition to the light-in-weight requirement, Singh et al [3] add good durability (generally 4k-8k h and 30k-60k h for military and commercial airlines, respectively), low costs (initial cost for purchasing and maintenance) and good fabricability as desirable features for aeronautical parts.…”

Section: Introductionmentioning

confidence: 99%

Ti6Al4V-ELI Alloy Manufactured via Laser Powder-Bed Fusion and Heat-Treated below and above the β-Transus: Effects of Sample Thickness and Sandblasting Post-Process

2022

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Ti6Al4V-ELI is the most-used lightweight alloy in the aerospace industrial sector thanks to its high mechanical strength and corrosion resistance. The present paper aims, firstly, to evaluate the effects induced by different heat treatments, which were performed above and below the β-transus temperature on Ti6Al4V-ELI samples manufactured via Laser Powder-Bed Fusion in different orientations (XZ, XY, Z and 45°). The first set of tensile samples and bars were heat-treated at 1050 °C × 1 h, while the second and third set were heat-treated at 704 °C × 120′ following the AMS2801 standard specification, and at 740 °C × 130′. These heat treatments were chosen to improve the as-built mechanical properties according to the ASTM F3001 and also ASTM F2924-14 standard specifications. Optical and SEM measurements reveal primary, secondary and tertiary α-laths below the β-transus, while above this temperature, the microstructure varies in relation to the sample’s thickness. Secondly, this work analyzed the results obtained after a sandblasting process, which was performed on half of all the available heat-treated tensile samples, through XRD and Vickers microhardness measurements. XRD analysis also highlighted the presence of α2-Ti3Al and TiAl3 precipitates and the microstructural change in terms of the α-phase.

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A Review on Additive Manufacturing of Titanium Alloys for Aerospace Applications: Directed Energy Deposition and Beyond Ti-6Al-4V

Cited by 174 publications

References 88 publications

The Conversion of Calcium-Containing Phases and Their Separation with NaCl in Molten Salt Chlorinated Slags at High Temperature

The Conversion of Calcium-Containing Phases and Their Separation with NaCl in Molten Salt Chlorinated Slags at High Temperature

Feedback Control of Melt Pool Area in Selective Laser Melting Additive Manufacturing Process

Ti6Al4V-ELI Alloy Manufactured via Laser Powder-Bed Fusion and Heat-Treated below and above the β-Transus: Effects of Sample Thickness and Sandblasting Post-Process

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