Assessment of the effect of isolated porosity defects on the fatigue performance of additive manufactured titanium alloy

Biswal, Romali; Syed, Abdul Khadar; Zhang, Xiang

doi:10.1016/j.addma.2018.08.024

Cited by 58 publications

(63 citation statements)

References 34 publications

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“…When the printed powder was melted, spherical droplets were preferentially formed to minimize surface formation energy . When the subsequent powder continued to melt, laser energy might not be sufficient to melt the new thicker powder layer . Manufacturing defects were likely generated by the incomplete melting of 15‐5PH precursor particles, as manufacturing defects formed at the melted pool line interface or between layers.…”

Section: Resultsmentioning

confidence: 99%

“…However, manufacturing defects have an important effect on mechanical properties and corrosion resistance. Related studies using tensile tests and finite element simulation have shown that the elongation of metal considerably decreased due to manufacturing defects. Liverani et al showed that cracks mainly originated from manufacturing defects, such as voids, binding defects, and oxide.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Manufacturing Parameters on the Mechanical and Corrosion Behavior of Selective Laser‐Melted 15‐5PH Stainless Steel

Wang

Dong

Kong

et al. 2019

steel research int.

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The effect of manufacturing parameters on mechanical and corrosion resistance is investigated using tensile tests and electrochemical experiments for selective laser-melted 15-5PH stainless steel. The results demonstrate that when laser power is decreased to 150 W and scanning speed increased to 1400 mm s À1 , manufacturing defects increase. Plasticity and corrosion resistance reduce significantly. Cracks mainly originate from manufacturing defects and extend along the interface between molten pools. Corrosion occurs near manufacturing defects. Finally, the most suitable laser energy density is 130 J mm À3 for 15-5PH stainless steel.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Manufacturing Parameters on the Mechanical and Corrosion Behavior of Selective Laser‐Melted 15‐5PH Stainless Steel

Wang

Dong

Kong

et al. 2019

steel research int.

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“…where Kt is the stress concentration factor and the value for spherical internal pores is 2.08 [25]. Kf is the notch fatigue factor determined by the ratio of the fatigue limit of the reference (or smooth) specimens to the fatigue limit of the porosity specimens.…”

Section: Modified Kitagawa-takahashi Diagrammentioning

confidence: 99%

“…In terms of modelling of defects and fatigue life prediction, there are three approaches in the literature, namely, statistical (such as the weakest link theory [21][22][23][24]), classic notch fatigue method treating porosity as a stress raiser [25][26][27], and fracture mechanics approach [9,[28][29][30][31][32][33]. The statistical approaches discussed in [22][23][24] have been used effectively for correlating fatigue life with the initial distribution of porosity obtained from X-ray computed tomography.…”

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

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156

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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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“…13 It is well documented that porosity can result in fatigue crack initiation. 5,10,[14][15][16][17][18][19][20] In the work presented herein, the critical size of the pores that are prone to fatigue cracks is investigated and quantified for Inconel 718 material produced by SLM.…”

Section: Introductionmentioning

confidence: 99%

ICME Approach to Determining Critical Pore Size of IN718 Produced by Selective Laser Melting

Sangid

Ravi

Prithivirajan

et al. 2019

JOM

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A degree of porosity is expected in additively manufactured (AM) materials. To aid in the qualification of AM materials, the smallest pore size that results in a debit in the fatigue performance is quantified. In the work presented herein, crystal plasticity simulations are used to identify the stress concentration around pores of various sizes, revealing that a single 20-lm pore or two 10-lm pores (with centers spaced 15 lm apart) localize stress at the pore, as opposed to elsewhere in the microstructure. In situ microtomography and far-field high-energy x-ray diffraction microscopy were used to identify crack formation and the evolution of the grain-level micromechanical fields during cyclic loading. Eighteen cracks were observed (15 at pores, 3 at the surface) at highly stressed grains in a sample, although most did not propagate. The dominant crack was seen to originate from the free surface, which is rationalized by fracture mechanics.

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Assessment of the effect of isolated porosity defects on the fatigue performance of additive manufactured titanium alloy

Cited by 58 publications

References 34 publications

Effect of Manufacturing Parameters on the Mechanical and Corrosion Behavior of Selective Laser‐Melted 15‐5PH Stainless Steel

Effect of Manufacturing Parameters on the Mechanical and Corrosion Behavior of Selective Laser‐Melted 15‐5PH Stainless Steel

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

ICME Approach to Determining Critical Pore Size of IN718 Produced by Selective Laser Melting

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Assessment of the effect of isolated porosity defects on the fatigue performance of additive manufactured titanium alloy

Cited by 58 publications

References 34 publications

Effect of Manufacturing Parameters on the Mechanical and Corrosion Behavior of Selective Laser‐Melted 15‐5PH Stainless Steel

Effect of Manufacturing Parameters on the Mechanical and Corrosion Behavior of Selective Laser‐Melted 15‐5PH Stainless Steel

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

ICME Approach to Determining Critical Pore Size of IN718 Produced by Selective Laser Melting

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