PSI - Issue 42

Litton Bhandari et al. / Procedia Structural Integrity 42 (2022) 529–536

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Bhandari et al. / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 2. Microstructure of SLM Ti6Al4V alloy (a) As-built (b) Heat treated

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Build Direction

Fig. 3. Reconstructed prior β grains (a) As-built (b) Heat treated

solute and higher deformation of the crystal structure and thus results in wider XRD peaks. The peaks narrow down with the heat treatment and thus indicates the α ’ martensitic microstructure decomposed into α + β microstructure.

3.2. Mechanical properties

A surface roughness (Ra) of 3.6 ± 1.2 µ m with a density of 99.5% was achieved. The surface morphology of the as-fabricated Ti6Al4V alloy is shown in Figure 5. The Vickers’ hardness of SLM Ti6Al4V alloy is comparatively larger than the conventional Ti6Al4V alloy (Je bieshia et al. (2020)). The mechanical properties along with the Vickers’ hardness has been tabulated in Table 3.

Table 3. Mechanical Properties of vertically oriented heat treated Ti6Al4V alloy

Yield Strength (MPa) Tensile Strength (MPa) Elongation (%) Microhardness (HV) 808 ± 5 872 ± 12 14.4 ± 2.1 389 ± 8

3.3. Fatigue Performance and Fractographic analysis

The room temperature defect-based stress-life curve at stress ratio of -1 is shown in Figure 6. The square root of the defect area was considered as defect parameter. The endurance limit was found to be 300 MPa. The fatigue behavior