Intrinsically ductile failure in a nanocrystalline beta titanium alloy

A nanocrystalline bcc Ti67.4Nb24.6Zr5Sn3 alloy is shown to fracture in an intrinsically ductile manner with exceptionally large dimples (up to 10 mu m) which are two orders of magnitude greater than the grain size (approximate to 40nm). This large plasticity length scale is attributed to a combination of low shear modulus (approximate to 27GPa), high Poisson's ratio (approximate to 0.4) and ultrahigh strength (UTS approximate to 1.1GPa), close to the ideal shear stress, which facilitates ideal shear deformation to promote transgranular shear.