Showing papers by "David Bacon published in 1986"
TL;DR: In this article, four pairwise potentials have been found to be suitable for the simulation by computer of stacking faults and dislocation core configurations in model crystals having the hexagonal-close-packed structure.
Abstract: Four pair-wise potentials have been found to be suitable for the simulation by computer of stacking faults and dislocation core configurations in model crystals having the hexagonal-close-packed structure. The potentials define stress-free perfect crystals and have markedly different ranges and shapes, but the crystals have very similar elastic properties. The stability of translational stacking faults on basal and non-basal planes has been investigated, and it is concluded that stable faults can exist on all the planes considered. The translation vectors and volume expansions associated with the faults are reasonably well understood in terms of the hard-sphere model of the structure, irrespective of the form of the potential, and changes in atom coordination at the non-basal faults may be used to estimate the fault energy. The potentials are used in parts II and III to investigate dislocation behaviour.
85 citations
TL;DR: The energy and atomic structure of hexagonal-close-packed (h.c.p.) metals have been investigated using computer simulation as discussed by the authors, and three distinctly different interatomic potential functions have been used in either equilibrium or non-equilibrium form.
Abstract: The energy and atomic structure of {1121}, {1122) and {1012} twin boundaries in the hexagonal-close-packed (h.c.p.) metals have been investigated using computer simulation. Three distinctly different interatomic potential functions have been used in either equilibrium or non-equilibrium form. It is predicted that only one form of boundary can occur for {1121} and {1012} twins, but several interfaces may exist for (1122} twins. The stable boundaries are, with one exception, associated with one or both of the symmetry operations of reflection and 2-fold rotation defined in the conventional theory of twinning. The good agreement between the results for all six model crystals suggests that the structures found here have general relevance to twin boundaries in real h.c.p. metals.
80 citations
TL;DR: The four pairwise potentials found in part I (Bacon and Liang 1986) to define model hexagonal-close-packed crystals in equilibrium have been used for the computer simulation of dislocation cores in the absence of external stress as mentioned in this paper.
Abstract: The four pair-wise potentials found in part I (Bacon and Liang 1986) to define model hexagonal-close-packed crystals in equilibrium have been used for the computer simulation of dislocation cores in the absence of external stress. Straight dislocations with Burgers vector b equal to either ⅓〈1120〉 or 1/3〈1123〉 have been considered. For the former, the screw and the edge lying along 〈1200〉 dissociate on the basal plane to a width expected from the stacking-fault energy found in part I, but not always to two Shockley partials. The screw in one crystal has a more stable core when the disregistry spreads on the {1100} prism plane. The stable core of the edge lying along 〈0001〉 is not dissociated in any of the models, and contains a microcrack in one case. The ⅓〈1123〉 edge dislocation lying along 〈1100〉 has two stable core states in all the crystals. One consists of combinations of {1121} and {1122} microtwins and microcracks, the precise form depending on the potential, and in the other the 〈1123〉 di...
56 citations
TL;DR: In this paper, the effects of uniaxial prestressing and increasing the temperature to 300°C on the bulk modulus of uncoated and coated graphites at room temperature were investigated.
9 citations
TL;DR: In this paper, the 4-point bend strength and strain to fracture at room temperature have been measured in three graphites at atmospheric pressure and at a gas pressure of 600 psi (4.14 MPa).
3 citations