Issue 78

S. Vantadori et alii, Fracture and Structural Integrity, 78 (2026) 432-453; DOI: 10.3221/IGF-ESIS.78.25

pronounced grain elongation suggests the development of a typical rolling-induced texture, which is expected to contribute to anisotropy in the mechanical response of the material. SEM-EDX analysis (Fig. 1(b)) reveals the presence of non-metallic SiO 2 inclusions, whereas no agglomerates of ZrO 2 nanoparticles are observed.

Figure 1: Microstructural characterisation of the AMC: (a) optical micrograph showing the grain structure; (b) SEM image revealing non metallic SiO 2 inclusions. Static tensile tests The quasi-static mechanical properties of the AMC are determined through tensile tests, according to the ASTM E8/E8M 22 standard [30]. The specimens are machined from a plate having a thickness of 10mm. The sizes of the specimens are shown in Fig. 2. A universal testing machine equipped with a 100kN load cell is used to perform the tests. Each specimen is secured in the machine wedge grips, and the testing apparatus is zeroed to avoid undesired preloads. The crosshead speed is set to 1.2 mm/min, corresponding to an apparent strain rate of 0.015 min -1 . Three specimens are tested.

R12.5

50.0

82.0

20.0

12.5

10.0

200.0

Figure 2: Tensile tests: geometry of the AMC specimen (sizes in mm).

Cyclic tensile tests The fatigue behaviour of the AMC is investigated through force-controlled constant amplitude axial fatigue tests, according to the ASTM E466-21 standard [31]. The specimens are machined from the aforementioned plate; however, in this case, the thickness is reduced to 4mm to comply with the standard specimen dimensions. The sizes of the specimens are reported in Fig. 3.

R64.0

10.0

20.0

8.0

10.0

4.0

63.0

Figure 3: Cyclic tensile tests: geometry of the AMC specimens (sizes in mm).

436