PSI - Issue 53

João Alves et al. / Procedia Structural Integrity 53 (2024) 236–245 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Table 5. Average mechanical properties obtained from Tensile test data for Ti-6Al-4V.

Young Module (GPa)

Yield Strength (MPa)

Ultimate Tensile Strength (MPa)

Fracture Strength (MPa)

Yield Strain (mm/mm)

Elongation (mm/mm)

Curve:

Nominal

105.9 107.9

1009

1129

852.5

0.0112 0.0185

0.1456

True

1030.5

1186.5

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Table 6. Plasticity properties obtained from Tensile test data for Ti-6Al-4V. Strain hardening exponent Strength coefficient (MPa) Average 0.0446 1358.17

The results from fatigue analysis are presented in Fig. 7. Using the equation obtained from the fatigue experimental data, it was possible to determine the fatigue limit stress, which had a value of 109.96 MPa. A similar result was obtained by some authors, such as Gong et al. (2015) and Masuo et al. (2018). The fatigue curve showed a very defined trend where fatigue life raises notoriously, with the reduction of the stress amplitude, unlike what is usually seen for other materials such as steel.

Fig. 6. Fatigue curve of a Ti-6Al-4V alloy manufactured by SLM.

The defect analysis showed excellent results since it had a low volume of spherical (equidimensional) shape defects. These volumes are in the projected defect area, as represented in Table 7. A lower value is notorious compared to the results obtained by Xu et al. (2021), which showed the suitability of the proposed procedure represented in Fig. 2, the parameters, and the conditions used for manufacturing the specimens. However, more studies would be necessary since the method used in the present research was nanotomography, and Xu et al. (2021) used a different method for counting defects, the optical microscope.

Table 7. Results obtained from the analysis of defects. Volume of defect ( μ m 3 ) Radius of defect ( μ m)

Area of surface defect ( μ m 2 )

Projected area of defect ( μ m 2 )

10

1.34 6.12

19.7 566

5.64 117

960