Showing papers in "Acta Metallurgica in 1965"

TL;DR: In this article, a growth equation for individual grains in single-phase materials is suggested, which is used to calculate a rate equation for normal grain growth and the size distribution in the material.

TL;DR: In this article, the role of carbides, mechanical twinning and slip in the initiation of cleavage microcracks in two coarse-grained vacuum-melted ferrites containing 0.035 and 0.007 per cent carbon was studied by means of tensile tests carried out between room temperature and −195°c in conjunction with special metallographic procedures.

TL;DR: In this article, a theory of steady state creep is presented which is based on the diffusion controlled motion of jogged screw dislocations, where the chemical forces on the jogs are balanced by the force on the dislocation due to the applied stress.

TL;DR: In this article, a semiquantitative theory has been developed for the formation of precipitate free zones at grain boundaries and the results have been used to develop a model of nucleation by vacancy/solute atom clusters.

TL;DR: In this article, the Mg-5 wt. % Zn alloy age hardens by the precipitation of a coherent transition lattice, MgZn, in the form of long thin rods perpendicular to the basal plane.

TL;DR: In this article, the size of locally yielded regions, the stress distribution, and displacements attending a crack in tension under plane stress have been calculated by extending the work of Dugdale and others.

TL;DR: A thin foil microscope study has been made of precipitation of the complex cubic carbide (Fe, Cr)23C6 from two Ni-Cr austenitic steels as discussed by the authors.

TL;DR: In this article, the authors used the magnitude of permanent softening, τ s, as a measure of the contribution of long range internal stresses to work hardening in the case of alloys of cubic metals.

TL;DR: The nucleation and growth of S' precipitates in an aluminium-2.5% copper-1.2% magnesium alloy aged at 190°C have been examined by transmission electron microscopy as discussed by the authors.

TL;DR: Strain-rate cycling tests have been performed during the tensile deformation of single crystal and polycrystalline specimens of two zone-refined irons in the temperature range 78-300°K.

TL;DR: In this article, the Bowles-Mackenzie theory has been applied to this martensite transformation, assuming A (111) γ [121] γ lattice invariant shear system, instead of the (110) ε [110] ε system used to account for the more familiar transformation to internally twinned martensites, and the theoretical predictions were found to be in good agreement with the experimental results.

TL;DR: Three-stage hardening in tantalum single crystals deformed in tension over limited range of orientations, temperatures and strain rates was studied in this paper, where the authors showed that the hardening can be achieved by three stages.

TL;DR: In this paper, the activation energies for grain boundary migration in bicrystals of zone-refined lead as a function of misorientation about a common 〈100〉 tilt axis were measured.

TL;DR: In this paper, a model-independent description of mechanical twinning is presented and it is shown that slip, which may be induced concurrent with twinning, serves as an energy dissipation process and predicts phenomena such as negative strain-rate sensitivity and a positive temperature dependence for the deformation.

TL;DR: In this paper, the activation volume and energy have been determined for yielding, flow and stress relaxation in high purity polycrystalline niobium wire containing less than 100 ppm of interstitial impurities.

TL;DR: In this article, it is suggested that hydrogen pressure builds up in propagating microcracks and aids the applied stress in the fracturing process, and also that the rate of crack propagation may be a hydrogen diffusion controlled process.

TL;DR: In this paper, the authors used magnetic resonance lines to study self diffusion of aluminum in high purity aluminum and in solid solution alloys of aluminum with zinc, magnesium and copper, and found that the rate of aluminum diffusion increases with increased solute content, and that the activation energy for aluminum diffusion decreases.

TL;DR: In this paper, a kinetic model is developed for the growth of spherical Guinier-Preston zones based on the diffusion of solute-vacancy complexes to the zones under certain favorable physical conditions.

TL;DR: In this article, the authors show that at constant composition, ruthenium alloys exhibit diffusionless α(b.c., f.c.), γ(f.c.) and ϵ(h.c.c.).

TL;DR: The dislocation arrangements in austenite, deformed above the athermal M s, temperature, are dependent upon alloy composition, strain and deformation temperature and influence the subsequent transformation to martensite on quenching as mentioned in this paper.

TL;DR: In this paper, the elastic constants of f.c.c have been measured as a function of temperature in the range 200-350°K at fixed compositions within the range 28-40 at.

TL;DR: In this article, the elastic constants of single crystals of the nickel-copper alloy system were determined by an ultrasonic pulse-echo technique, and they were proportional to the nickel concentration up to 70 at room temperature.

TL;DR: In this article, surface diffusivities were found from measurements of grain boundary groove widths on specimens annealed in vacuo, in nitrogen plus hydrogen mixtures and in oxygen at different pressures.

TL;DR: Theories on the origin of slip were assessed from the observations made on the nucleation and propagation of slip as mentioned in this paper, and the metallographic evidence supported the Hall-Petch theory of propagation from grain to grain.

TL;DR: In this paper, the free energies of phase formation were determined from measurement of magnesium vapor pressures over a series of alloys, while the enthalpies were determined calorimetrically with a differential acid solution calorimeter.

TL;DR: The Flieβkurve vielkristalliner metalle durchlauft bei hohen Temperaturen ein Maximum bei Verformungsgraden um 100% and fallt danach auf einen stationaren Wert ab.

TL;DR: In this paper, radioactive Xe has been injected into Al, A1 2 O 3, Ta, Ta 2 O 5, Ag, and Au at energies up to 40 keV, and the targets then heated in vacuum to determine the release behavior.

TL;DR: In this article, the Abhangigkeit der Quergleitspannung τIII of KupferLegierungs with Gallium-bzw. Germaniumzusatz and Elektronenkonzentrationen 1,00 ≤ e/a ≤ 1,15 wurden im Zug verformt.