Reynolds Group Holdings

About: Reynolds Group Holdings is a based out in . It is known for research contribution in the topics: Alloy & Alonizing. The organization has 587 authors who have published 566 publications receiving 7705 citations. The organization is also known as: Reynolds Metals Company.

The effect of plastic deformation on Al2CuLi (T1) precipitation

Abstract: The enhancement ofT1 precipitation in Al-Li-Cu alloys by plastic deformation prior to aging (that is, cold work) and the subsequent increase in alloy strength is investigated. The increased understanding of the role of matrix dislocations in the nucleation and growth ofT1 plates, discussed in the previous paper,[1] permits a detailed study of the phenomenon. In this paper, the effect of different levels of plastic strain on theT1 particle distributions as a function of aging time at 190 °C is quantified, and the subsequent influence on tensile properties is thereby described. The effect of plastic deformation is shown to decrease theT1 plate length and thickness, increase the number density by almost two orders of magnitude, increase the yield strength by 100 MPa, while simultaneously reaching peak strength in 20 pct of the time required without plastic deformation.

Mechanism of Al 2 CuLi ( T 1 ) nucleation and growth

Abstract: Conventional strain contrast transmission electron microscopy (CTEM) and high-resolution transmission electron microscopy (HRTEM) were performed to establish the nucleation and growth mechanism of Al2CuLi (T1) precipitates in an Al-Li-Cu alloy. It is shown that the growth mechanism ofT 1 precipitate plates occurs by the diffusional glide of growth ledges composed of b = 1/6〈112〉 partial dislocations on 111 matrix planes and that the growth ledges migrate by the ledge-kink mechanism, as previously suggested by Cassadaet al. 1 for this system.T 1 plate nucleation is modeled as the dissociation of a perfect b = 1/2〈110〉 matrix dislocation in the vicinity of a dislocation jog. The coordinated dissociation of the dislocation line segments on each side of the sessile jog provides the displacement necessary for the formation of a new hexagonal plate or plate ledge. Strain contrast analysis of the Burgers vector of plate edges and the edges of growth ledges indicates the stacking of partial dislocations is of mixed displacement. Formerly Graduate Student, Department of Materials Science, University of Virginia,

The effects of preaging treatments on aging kinetics and mechanical properties in AA6111 aluminum autobody sheet

Abstract: The automotive paint bake cycle is used to impart a modest artificial aging response, referred to as the paint bake response (PBR), in Al-Mg-Si-Cu autobody sheet alloys following stamping. This aging response acts to increase the dent resistance of exterior automotive panels and allows for greater down gaging. Unfortunately, the short duration of the paint bake cycle (as dictated by production demands) is generally insufficient to exploit more than a small fraction of the age-hardening potential of the alloys. The application of a preaging treatment immediately after quenching from solution heat treatment has been shown to be effective in increasing the PBR by up to a factor of 4, while at the same time improving the formability of the alloy and reducing the natural aging rate. Through the use of atomic resolution microscopy and differential scanning calorimetry, the mechanism of preaging can be shown to be the result of changes in the precipitation sequence of metastable variants of Mg2Si, resulting in an increase in the precipitation kinetics during the aging cycle and a finer distribution of strengthening precipitates. The model proposes that preaging biases the formation of disordered clusters, which subsequently undergo partial dissolution during higher temperature thermal excursions. The cluster dissolution is associated with both an increase in the matrix concentration of elemental solute (Mg and Si) and a transient flux in vacancies that were previously entrained with the disordered clusters. The dissolution results in the formation of an intermediate metastable phase and an enhancement in the aging kinetics of β″ precipitates. The enhancement in aging kinetics allows superior final component strength at higher production rates, as well as allowing for lower automotive paint bake temperatures.

Easy-open wall

Abstract: An easy-open construction for a container wherein a panel principally defined by a rupturable score line in a wall is opened by operating a tab having one end adapted to press against the panel at a position spaced from the score line and overlying only a small portion of the opening left by the panel in its opened position. The other end of the tab is liftable to open the panel and is returnable directly to its original position next to the wall. The tab and panel remain secured to the wall after the panel has been moved to its open position.

Development of localized orientation gradients in fcc polycrystals

Abstract: A finite-element formulation which derives constitutive response from crystal plasticity theory is used to examine localized deformation in fcc polycrystals. The polycrystals are (simple) idealized three-dimensional arrangements of grains, and many elements per grain. Non-uniform deformations within individual grains lead to the development of domains that are separated by boundaries of high misorientation. Also, localized shearing is seen to occur on a microscopic scale of grain dimensions. The important consequence. of these simulations is that the predicted local inhomogeneities are meeting various requirements that make them possible nucleation sites for recrystallization.