Intrinsically ductile failure in a nanocrystalline beta titanium alloy
journal contribution
posted on 2011-12-01, 00:00authored byWei XuWei Xu, Roberto B Figueiredo, Xiaolin Wu, Simon Pauly, Mihai Stoica, Juergen Eckert, Terence G Langdon, Kenong Xia
A nanocrystalline bcc Ti67.4Nb24.6Zr5Sn3 alloy is shown to fracture in an intrinsically ductile manner with exceptionally large dimples (up to 10 µm) which are two orders of magnitude greater than the grain size (≈ 40 nm). This large plasticity length scale is attributed to a combination of low shear modulus (≈ 27 GPa), high Poisson's ratio (≈ 0.4) and ultrahigh strength (UTS ≈ 1.1 GPa), close to the ideal shear stress, which facilitates ideal shear deformation to promote transgranular shear.