Crack nucleation and growth in α/β titanium alloy with lamellar microstructure under uniaxial tension: 3D X-ray tomography analysis

N. Dang (1) , L. Liu , J. Adrien (2) , S. Cazottes (2) , W. Xiao (1) , C. Ma (1) , L. Zhou , E. Maire (2)

1 BUAA - Beihang University
2 MATEIS - Matériaux, ingénierie et science [Villeurbanne]

In situ tensile tests were carried out on notch axisymmetric samples of as-cast (α+β) Ti alloy to analyze evolution of void/micro-crack with the help of X-ray Synchrotron tomography. The results indicate that junctions or boundaries of α colonies could be the most vulnerable sites for voids nucleation. In addition, during the growth and coalescence procedure, “ligaments” could be observed on the voids/micro-crack. A “bypassing & fracture” propagating approach was proposed and validated to interpret the existence of “ligaments”. In the propagating procedure, due to lacking of hard precipitations, microstructure zone and other inserting colony could play a role as hard obstacle in the growing path. This could induce a “bypassing & fracture” propagating approach for void coalescence and micro-crack growth. © 2019 Elsevier B.V.

Mots clés: Aluminum alloys; Coalescence; Crack propagation; Cracks; Imaging systems; Metal testing; Microstructure; Nucleation; Tensile testing; Ternary alloys; Tomography; Vanadium alloys; X rays; Bypassing behavior; In-situ tensile test; Ti-6Al-4V alloy; Void propagation; X-ray tomography; Titanium alloys

Domaines: Mécanique des matériaux [physics.class-ph]

N. Dang, L. Liu, J. Adrien, S. Cazottes, W. Xiao, et al.. Crack nucleation and growth in α/β titanium alloy with lamellar microstructure under uniaxial tension: 3D X-ray tomography analysis. Materials Science and Engineering: A, 2019, 747, pp.154-160. ⟨10.1016/j.msea.2019.01.065⟩. ⟨hal-02405467⟩