Investigation of Mechanical and Microstructural Characteristics of Al–Mg Compounds

Abstract

The significantly increasing interest and extensive research activity in the field of magnesium-based materials are ascribed to the demand for a consistent implementation of lightweight construction. The automobile industry has contributed to this development through a continuing demand for decreased exhaust emissions and reduced fuel consumption. One highly effective way to achieve reduced vehicle weight is the application of alternative materials with similar properties but lower mass. For example, magnesium has a higher rigidity than aluminum as well as a higher strength-to-weight ratio than steel. It is also excellent for machining. As a result, magnesium compounds are particularly well suited to lightweight constructions. The main limiting factor for the application of magnesium is its relatively low level of corrosion stability. One possibility to protect materials from corrosion is to use corrosion-resistant metallic coatings. This approach has an advantage over varnish or plastic layers because of the higher mechanical resistance of the coating. Two-or multilayer metallic compounds, which can be several millimeters thick, are produced mainly by using mechanical processes. The most commonly applied processes are roll or explosion cladding as well as a variety of extrusion methods. Whereas in coating techniques, the intended change in material properties or functional characteristics is restricted to the area near the surface, these approaches allow the formation of semifinished cross sections with optimized structures. Recent investigations into compound extrusion reveal that metallic bonding is possible between aluminum (face-centered cubic crystal system) and magnesium (hexagonal close-packed system), despite their different lattice structures. A distinct diffusion zone between a wrought magnesium alloy (AZ31) and a standard aluminum alloy (6060) was achieved. [1] The extensive study into identification and characterization of the formed microstructure and the properties of the created compound demonstrates an alternative approach for compound manufacturing.

Manufacturing Al/Mg composite materials

“…Previous research results confirm that the chemical prerequisites for diffusion in the solid phase are met in an aluminum/magnesium pairing [1,2]. Normally, substance transport across phase interface is possible only if the system is comprised of a series of mixed crystals.…”

“…3) established the preconditions for ascertaining interface reactions between aluminum and magnesium under forming conditions [1]. The test arrangement is based on the process principle of lateral extrusion.…”

“…These are two intermetallic phases that are known from the aluminummagnesium two-material system. [1].…”

“…9 (left), i.e. the interface was situated in the [1] symmetrical plane of the shear samples. In order to determine the composite strength until fracture, the samples were subject to a continuously increasing test force.…”

“…The boundary layer is characterized by a brittle deformation behavior [1], but the determined values also contain a ductile component, caused by fracture sections partially in the base metal due to non-ideal boundary layer evenness and symmetricality (Fig. 10).…”