The plastic anisotropy was measured for a commercial AZ31 magnesium sheet and compared with results from a model calculation using a self consistent viscoplastic model. The anisotropy of plastic flow stresses can be explained by the off-basal character of the texture and the activation of the prismatic slip in addition to the basal, pyramidal slip and the > < 1 1 01 } 2 1 01 { twinning system. The strain anisotropy r ( r = ew/et ; ew, et – strains in width and thickness directions of a sheet material ), as obtained from model calculations, fits qualitatively with in-situ measured values. Results from these model calculations are compared with texture simulations and discussed in further consideration of the microstructure of the sheet material.

Samples of the magnesium alloy AZ31 (3 wt% Al, 1 wt% Zn, balance Mg) with two microstructures, recrystallized and squeeze cast, were rolled at room temperature. The initial texture and the final cold rolling texture were investigated by X-ray diffraction. The cold rolling texture of both examined initial microstructures consists of two fibres, representing the familiar double peak in the basal pole tilted ±15° from the normal direction to the rolling direction. A systematic texture modelling was performed using a viscoplastic Taylor model, based on different combinations of four slip modes and one twinning mode. The best agreement with experiment can be achieved for a combination of 〈a〉-basal, 〈a〉-prismatic, 〈c+a〉-pyramidal slip systems together with the {011̄2}〈011̄1̄〉 twinning system.

Magnesium wrought alloys offer a large potential for structural applications due to improved mechanical properties and microstructural homogeneity compared to thin-walled cast magnesium parts. Generally, the processing and its parameters influence the development of the wrought microstructure which additionally has a significant influence on mechanical properties. Rolling experiments were carried out on magnesium AZ31 cast material at various temperatures and using various degrees of forming. An additional heat treatment at each rolling temperature was conducted in order to separate dynamic and static processes. Furthermore, stepwise rolling experiments were carried out at 400degreesC specifically. Metallographic analysis and texture measurements were used to explain the microstructural evolution during rolling.

Car weight corresponds directly to fuel consumption and driving performance. So in order to improve the fuel efficiency and performance of a car the weight has to be reduced. Magnesium as a light metal offers a wide range of weight saving opportunities, especially Magnesium wrought alloys with their improved mechanical properties have a high potential for structural applications. Mechanical properties in terms of their quality and anisotropy are dependent on the microstructure of the material and can be characterized by their degree of inhomogeneity, their grain size distribution and their crystallographic texture. Therefore the orientation distribution of grains, the grain size, its size distribution, the chemical composition (precipitates) itself influence the mechanical parameters and their anisotropy. In this presentation first results of mechanical anisotropy are given: differences in yield stress, r-values and their relation to the texture. This correlation between microstructure and mechanical behaviour offers the possibility to improve the mechanical properties, e.g. due to an optimisation of the material production process.

Two aspects of the deformation behavior of magnesium sheets are the subject of this paper. First it will give a mechanical characterization of a commercial magnesium with a focus on the anisotropy and the possible microstructural causes of this behavior. The rolling process will be part of the second aspect. The aim is to show the influence of the parameters on the microstructure and texture and how this could affect the anisotropy in the rolled sheets.

Mechanical properties in terms of their quality and anisotropy are dependent on the microstructure of the material and can be characterized by their degree of inhomogeneity, their grain size distribution and their crystallographic texture. A correlation between microstructure and mechanical behaviour offers the possibility to improve these properties, e. g. due to an optimisation of the material production process. A short overview is given and first results are presented.

Strain localization during tensile deformation of cold-rolled and annealed 7Mn steel were investigated under various strain rates and deformation temperatures. The retained austenite grain size, strain rate and deformation temperature all have remarkable influences on the appearance of PLC bands. Higher strain rate clearly suppressed the formation of PLC bands whilst deformation temperature had a more complicated influence. During the room-temperature deformation at the quasistatic strain rate of 6.67 × 10−4/s, Lüders bands appeared in all specimens whilst PLC bands only in the specimens that were annealed above 700 °C. Digital image correlation (DIC) analysis showed the specimen annealed at 700 °C exhibited the type A PLC bands during the entire period of deformation; whilst the one annealed at 720 °C showed the more complicated type A+B bands before 600s and the type A bands afterward. All of these phenomena have been discussed in relation to the interaction of C atoms/C-Mn pairs and dislocations for sound interpretation.

The cyclic hardening behaviour of pure polycrystalline aluminium tested in tension-compression under strain control is reported. Diagrams of stress amplitude vs. cumulative plastic strain exhibit a softening stage for small plastic strain amplitudes ϵa. A saturation behaviour of the stress amplitude at large cumulative strains is evident for all ϵa. A simple power-law dependence between the saturation stress and ϵa is found.

ABSTRACT The equivalence of the deformation behavior of metallic materials under various modes of straining is the underlying assumption in numerous unified constitutive models of plastic deformation. In the present work, the fulfillment of this assumption was experimentally checked by studying the steady state and the transient deformation of pure Al, Al-2% Mg, and Al-10% Mn, both in creep and under constant strain rate (CSR) tests. For all materials investigated, the equivalence of steady state deformation in creep and under CSR condition was affirmed. The transient characteristics of the two straining modes were also found to obey a relation that substantiates the mentioned assumption.