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.

A universal theory for the bonding of metallic materials does not exist. For new material combinations and new joining technologies the bonding properties have to be examined individually. The factors affecting bonding behavior and characteristic like the bond strength have to be investigated. This paper presents a method for generating composites by a forming process and shows innovative possibilities to test and evaluate relevant parameters of the bonding process

The realization of light weight design of components with local, load adapted properties is a major goal in the development of new manufacturing and processing methods of metal composite materials. A main challenge in the manufacturing of compounds by forming consists in the realization of the necessary conditions for the initiation of the diffusion process and the generation of metallic bonding. A combination of high contact tensions with specific forming conditions such as temperature distribution and surface enlargement is required in order to initiate the diffusion of atoms during the forming process. The article presents FEM-simulation and investigation of contact and forming conditions of aluminum-magnesium composites with respect to an incremental forming method. The characteristics of the compound materials, surface enlargement and local forming conditions as well as temperature gradients are important factors for the diffusion processes. The investigation of co ntact conditions during compound formation is a prerequisite for the further design of forming methods and the base for new approaches of generating composites of two light metal alloys into products with favorable properties such as high specific strength and corrosion resistance

Schlüsselwörter: Metallverbunde / Festkörperdiffusion / indirektes Strangpressen / Leichtbau / The paper presents first results of indirect extrusion of Al/Mg compounds. In earlier tests of lateral extrusion and hydrostatic extrusion first basic insights into the compound generation were gained. The current investigation focuses on another application of the compound manufacturing approach using industrial equipment and the verification of basic results. The calculation of the material flow, the design of appropriate extrusion dies, the design and preparation of the compound billets and the selection of processing parameters are major tasks. By completely encasing the Mg core with Al material including the rod faces the pre-advancement of the core material was prevented. Two different extrusion ratios were selected in order to detect the influence of deformation on the bond generation. The billet geometry, the volume ratio between Al and Mg, the billet treatment and the processing parameters remained constant throughout the test series for better comparability of results. The process and die design were aided by FEM simulation. The main goal in calculation was a nearly equal material flow of both the Al and Mg partners. The generation of a metal bond was achieved. As already observed in lateral and hydrostatic extrusion the interface is characterised by hard brittle intermetallic phases with high failure rates due to breakage. The paper discusses failure mechanisms and means for controlling this effects.

Excellent mechanical properties and corrosion resistance combined with low weight qualify b-titanium materials for lightweight applications in aviation, automotive and energy engineering. Thus far, actual applications of these materials have been limited due to high material costs and limited processing knowledge. One approach for developing resource-efficient manufacturing methods is the application of incremental forming methods. This article focuses on the development of the incremental spin extrusion process, which creates hollow profiles from solid bars. This method allows hollow shape manufacturing with a much higher flexibility than other forming methods and a significantly improved material utilization in comparison to machining methods, such as deep hole drilling. Beta-titanium alloys basically have very good cold forming suitability and the resulting material properties can be controlled. The application of incremental forming methods with high hydrostatic compressive stress is a promising manufacturing approach. The b-titanium Ti-10V-2Fe-3Al material has an excellent combination of the properties strength, ductility and fatigue strength. In order to utilize these properties the forming conditions and the temperature control need to be optimized. The investigations show that the Ti-10V-2Fe-3Al material can be formed only in a narrow semi-hot forming temperature window. The paper describes the investigation and presents results on the design of partial forming process sequences, forming properties, microstructure formation and failure prevention. The process design objective is a very fine microstructure with a homogeneous secondary a-phase and very small grained b-phase.