Burgers vector of dislocations in an icosahedral ${\mathrm{Al}}_{62}$${\mathrm{Cu}}_{25.5}$${\mathrm{Fe}}_{12.5}$ quasicrystal determined by means of convergent-beam electron diffraction

Dislocations in an ${\mathrm{Al}}_{62}$ ${\mathrm{Cu}}_{25.5}$ ${\mathrm{Fe}}_{12.5}$ face-centered icosahedral quasicrystal were studied by means of the contrast experiment and defocus convergent-beam electron diffraction technique. The indices of the six-dimensional Burgers vector of the dislocations were determined to be 1/2[1 -1 1 -1 0 0]. The projection ${\mathbf{b}}_{\mathrm{\parallel }}$ of this six-dimensional Burgers vector in the three-dimensional physical space is exactly parallel to a twofold axis of the icosahedron. The magnitude ‖${\mathbf{b}}_{\mathrm{\parallel }}$‖=0.291 nm was calculated when a=0.896 nm is taken for the lattice constant of the face-centered icosahedral phase.