Self-organization of shear bands in titanium and Ti–6Al–4V alloy

The use of hat-shaped specimens to study the high strain rate shear behaviour of Ti–6Al–4V

“…A lot of research has already been conducted on adiabatic shear banding and failure in this material. Several dynamic experimental techniques have been used: shear compression specimen test (SCS) [15], torsion of thin walled tubes [16], thick-walled cylinder implosion test [17], modified double shear test [18], impact on a plate [19], etc. A common feature of these experiments is that the specimen is deformed until either the material fails or the energy of the impact is fully absorbed, since interrupting the experiment at a certain level of deformation it is not obvious.…”

Formation of adiabatic shear band in metal matrix composites

“…At high loading rates, the lack of time for global heat conduction combined with inhomogeneous plastic deformation will induce inhomogeneous heating which in turn leads to local material softening and additional plastic deformation so that localized shear bands are finally formed. Also, recent research works from Meyers and co-workers (Meyers et al, 2001;Xue et al, 2002) have demonstrated that adiabatic shear bands often exhibit a self-organization pattern.…”

Controlled Pre-Corrosion Attack and Ultrasonic Fatigue Endurance of Titanium Alloy Ti-6Al-4V

“…Since some of specimens in this work has been subjected to pre-corrosion attack, the crack initiation site for them has been frequently located at the surface of specimen, associated with high stress concentration induced by pitting. The crack initiation site was associated with the high stress concentration at the surface of specimen (presence of pitting generated by pre-corrosion), accompanied with plastic deformation at microscopic scale (micro-voids coalescence), which is observed in Figure 12c (Dominguez-Almaraz et al 2014;Xue et al 2002). The nucleation of micro-voids under ultrasonic fatigue leads to micro-cracks, which is the result of shear bands that facilitate the sites of failure inside the regions softened by thermal effect (Xue et al 2002;Zhang et al 2011).…”

“…The crack initiation site was associated with the high stress concentration at the surface of specimen (presence of pitting generated by pre-corrosion), accompanied with plastic deformation at microscopic scale (micro-voids coalescence), which is observed in Figure 12c (Dominguez-Almaraz et al 2014;Xue et al 2002). The nucleation of micro-voids under ultrasonic fatigue leads to micro-cracks, which is the result of shear bands that facilitate the sites of failure inside the regions softened by thermal effect (Xue et al 2002;Zhang et al 2011). Furthermore, the line of separation between the ductile-like (zone A) and brittle-like (zone B), of crack propagation is clearly denoted on Figure 12a.…”