Papers by Keyword: Al-Mg-Sc-Zr Alloy

Abstract: The effect of equal channel angular pressing (ECAP) on the structure and mechanical properties of Al-4% Mg-1.5% Mn-0.4% Zr and Al-4% Mg-1.5% Mn-0.4% Zr-0.4% Sc alloys in the initial as-cast state was studied. The ECAP processing was shown to lead to the formation of predominantly submicrocrystalline structure with an average grain size of 850 nm in the Al-Mg-Mn-Zr-Sc alloy and 1060 nm in the Al-Mg-Mn-Zr alloy. It is remarkable that both strength and ductility of the two alloys were enhanced by ECAP. The highest strength was observed in the Al–Mg–Mn–Zr–Sc alloy (UTS = 425MPa), in combination with elongation to failure of EL=17 %.

Abstract: The corrosion behavior of cold worked Al-Mg-Sc-Zr-Ni alloys prepared by vacuum induction melting in acidic chloride solution was studied. The morphological characteristics of the corroded specimens were examined by OM(optical microscopy), SEM
and EDX techniques. The results indicated that the intergranular and exfoliation corrosion susceptibility dramatically depended on the Ni content. The Al-Mg-Sc-Zr alloy with 0 and 0.5 wt.% Ni were lightly susceptible to intergranular corrosion as the precipitation of Mg2Al3 phases presented at grain boundaries and the Al3Ni particles were finely dispersive. The intergranular corrosion was enhanced by the Al3Ni particles enrichment and became pitting corrosion with increasing Ni to 1.0 wt.%. Finally, the exfoliation corrosion happened to the alloy with 2.0wt.% Ni. This trend correlated well with the electrochemical property and distribution of Al3Ni phases. The corrosion potential of Al3Ni intermetallic phase is nobler than the β phase and the matrix, which result in an appearance of galvanic coupling. In addition, the increase of Al3Ni particles enlarged the attack area and the inhomogeneous segments of Al3Ni and Al3Mg2 phases accelerated the localized corrosion.

Abstract: An Al-3%Mg-0.25%Sc-0.12%Zr alloy was deformed by triaxial forging at 20-400°C up to strains of about 3. A study of its textural evolution reveals the tendency towards three symmetrical variants of a <110><1 10 ><001> component. This experimental observation is supported by a 3D spatially resolved crystal plasticity analysis. Samples strained at room temperature undergo grain fragmentation in the form of fine substructures and relatively weak textures. Conversely, at 300°C and above, more homogeneous intergranular deformation and rotations give rise to stronger textures. This eventually encourages grain coalescence and thus the development of interpenetrating “orientation chains”, creating a new type of microstructure. The influence of this texture development on the specific work hardening behaviour is discussed.