Microstructural evolution and mechanical properties of Ti-6Al-4V wall deposited by pulsed plasma arc additive manufacturing

Lin, Jianjun; Lv, Yaohui; Liu, Y.X.; Xu, Bin; Sun, Zhe; Li, Z.G.; Wu, Yixiong

doi:10.1016/j.matdes.2016.04.018

Cited by 158 publications

(32 citation statements)

References 31 publications

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“…So far, to the best of the authors' knowledge, no systematic comparisons between the use of continuous or pulsed welding current during arc-based additive manufacturing can be found to the exception of [140,141]. In these works, the same group of authors studied, separately, the effect of using continuous or pulsed welding current during plasma-based additive manufacturing.…”

Section: Modulation Of the Heat Sourcementioning

confidence: 99%

“…Though the authors do not discuss these results in terms of the operating procedure, it is certain that the mechanism that promotes this increase in mechanical strength arise from the refined grain structure obtained when using a pulsed welding current. Both [140,141] are examples of welding knowledge transferred to additive manufacturing technologies.…”

Section: Modulation Of the Heat Sourcementioning

confidence: 99%

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Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Oliveira

Santos

Miranda

2020

Progress in Materials Science

422

134

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Additive manufacturing technologies based on melting and solidification have considerable similarities with fusion-based welding technologies, either by electric arc or high-power beams. However, several concepts are being introduced in additive manufacturing which have been extensively used in multipass arc welding with filler material. Therefore, clarification of fundamental definitions is important to establish a common background between welding and additive manufacturing research communities. This paper aims to review these concepts, highlighting the distinctive characteristics of fusion welding that can be embraced by additive manufacturing, namely the nature of rapid thermal cycles associated to small size and localized heat sources, the non-equilibrium nature of rapid solidification and its effects on: internal defects formation, phase transformations, residual stresses and distortions. Concerning process optimization, distinct criteria are proposed based on geometric, energetic and thermal considerations, allowing to determine an upper bound limit for the optimum hatch distance during additive manufacturing. Finally, a unified equation to compute the energy density is proposed. This equation enables to compare works performed with distinct equipment and experimental conditions, covering the major process parameters: power, travel speed, heat source dimension, hatch distance, deposited layer thickness and material grain size.

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Section: Modulation Of the Heat Sourcementioning

confidence: 99%

Section: Modulation Of the Heat Sourcementioning

confidence: 99%

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Oliveira

Santos

Miranda

2020

Progress in Materials Science

422

134

View full text Add to dashboard Cite

show abstract

“…Another cause for the test data scatter has been identified as the AM microstructure characteristics that are controlled by the cooling rate and peak temperature during deposition [12]. The volume fraction of α phase reported for WAAM Ti-6Al-4V is greater than 90% [13,14], with a predominantly Widmanstätten microstructure and an average α lath width of 1.5±1 µm [13][14][15]. The prior β grains are columnar and aligned in the build direction, which can lead to mechanical property anisotropy in terms of the tensile [5,16] and fatigue strength [5].…”

Section: Introductionmentioning

confidence: 99%

Criticality of porosity defects on the fatigue performance of wire + arc additive manufactured titanium alloy

Biswal

Zhang

Syed

et al. 2019

International Journal of Fatigue

140

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This study was aimed at investigating the effect of internal porosity on the fatigue strength of wire + arc additive manufactured titanium alloy (WAAM Ti-6Al-4V). Unlike similar titanium alloys built by the powder bed fusion processes, WAAM Ti-6Al-4V seldom contains gas pores. However, feedstock may get contaminated that may cause pores of considerable size in the built materials. Two types of specimens were tested: (1) control group without porosity referred to as reference specimens; (2) designed porosity group using contaminated wires to build the specimen gauge section, referred to as porosity specimens. Test results have shown that static strength of the two groups was comparable, but the elongation in porosity group was reduced by 60% and its fatigue strength was 33% lower than the control group. The stress intensity factor range of the crack initiating pore calculated by Murakami's approach has provided good correlation with the fatigue life. The kink point on the data fitting curve corresponds well with the threshold value of the stress intensity factor range found in the literature. For predicting the fatigue limit, a modified Kitagawa-Takahashi diagram was proposed consisting of three regions depending on porosity size. Critical pore diameter was found to be about 100 micrometres.

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“…Tungsten inert gas welding has been shifted to AM [18], the process being valuable for small quantities. Moreover, plasma arc resulted in an overall cost of 15% approximately with respect to laser [19], although unfeasible for thin parts or high-precision applications; hence, a hybrid system to lay Ti-wire metal over parts resulting from powder bed-based AM has been conceived [20].…”

Section: Introductionmentioning

confidence: 99%

Additive manufacturing by means of laser-aided directed metal deposition of titanium wire

Caiazzo

2018

Int J Adv Manuf Technol

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A number of innovative technologies are offered in the literature to the purpose of additive manufacturing. Among them, directed metal deposition of wire by means of laser beam is receiving increasing interest since important advantages are benefited in comparison with its powder-based counterpart. Nevertheless, a number of issues must be addressed: this paper aims to provide further understanding of the technology to give grounds to actual applications in an industrial environment. Single trace deposition of Ti-6Al-4V wire over homologous substrate is investigated; the laser power, the processing speed, and the amount of fed metal is changed. The geometrical responses (i.e., trace width, height, depth, shape angle, and dilution) in the cross-section are investigated as a function of the processing parameters. Namely, a global clear view of the responses is given as a function of power and deposited wire mass per unit time. Furthermore, possible occurrence of micro pores is discussed with respect to common international standards. Eventually, an investigation about changes in both the microstructure and the microhardness is addressed: an increase of hardness in the fusion zone is noticed as a consequence of non-diffusional martensitic transformation of the original α-β phases upon rapid cooling, with reduced extent of the heat-affected zone below 0.4 mm.

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Microstructural evolution and mechanical properties of Ti-6Al-4V wall deposited by pulsed plasma arc additive manufacturing

Cited by 158 publications

References 31 publications

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Criticality of porosity defects on the fatigue performance of wire + arc additive manufactured titanium alloy

Additive manufacturing by means of laser-aided directed metal deposition of titanium wire

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Microstructural evolution and mechanical properties of Ti-6Al-4V wall deposited by pulsed plasma arc additive manufacturing

Cited by 158 publications

References 31 publications

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice

Criticality of porosity defects on the fatigue performance of wire + arc additive manufactured titanium alloy

Additive manufacturing by means of laser-aided directed metal deposition of titanium wire

Contact Info

Product

Resources

About

Criticality of porosity defects on the fatigue performance of wire + arc additive manufactured titanium alloy