PSI - Issue 38

Benaouda Abdellaoui et al. / Procedia Structural Integrity 38 (2022) 116–131 Benaouda Abdellaoui et al / Structural Integrity Procedia 00 (2021) 000 – 000

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3. Tensile test 3.1. Conditions

The tensile tests were carried out on 21 bars 17-4PH developed by additive manufacturing according to standard NF EN ISO 6892-1: 2016 method B. The deformation measurements were made with an MFX200B extensometer verified according to NF EN ISO 9513 The Determination of Yield strength (offset 0.2%) was made with parallel straight method and elongation was measured manually after failure. The measurements taken during the tensile tests were rounded to MPa for stress, 0.1% for elongation and 1% for necking. 3.2. Results The mean results of the tensile tests on the three plates according to the horizontal (H) and Vertical (V) directions are presented in Table 4. Table 4. Summary of tensile test results

Mean Yield stress Rp 0,2% (MPa)

Elongation standard deviation

Necking standard deviation

Mean Necking Z 2 %

Mean Elongation A 5D 1 %

Mean Ultimate stress Rm (MPa)

Trays reference

Direction

0.764 0.957 0.289 0.408 1.000 0.479

1.000 1.500 1.155 2.082 1.000 1.414

H V H V H V

1433 1452 1440 1456 1441 1452

1276 1292 1279 1289 1281 1287

8.8 5.5 8.7 6.7 8.5 6.5

23 11 21 11 21 11

P2

P3

P4

All the trays have almost the same features. Similar results may be drawn for the Yield stresses and Ultimate stresses in both manufacturing directions (vertical/horizontal) However, there are differences for the elongation (31%) and for the necking (53%). 4. Characterization of fatigue materials with the E-N approach. 4.1. Strain-controlled fatigue bench The Fig. 4 shows strain-controlled fatigue testing (Low Fatigue cycle). The tests were performed on a side MTS hydraulic machines maximum capacity of 100 kN with an extensometer.

1 The percent elongation at failure denoted by A% defines the ability of a material to elongate before breaking when it is stressed in tension. 2 The coefficient of striction Z% corresponds to the measurement of the reduction of section after failure compared to the initial section.