Production process of low damage Al/Mg compounds and analysis of the basic mechanical properties as well as the strength of the interface

Abstract

Schlüsselwörter: Strangpressen / Aluminium/Magnesium-Verbund / Grenzschicht / Interfacefestigkeit / Simulation / A sign for changing ecological awareness is the increasing use of lightweight materials. Compound materials such as aluminum/magnesium compounds are a key technology for limiting consumption of energy and resources. In the following, a hydrostatic co-extrusion process and the manufactured compounds are investigated. Of special interest are the quality of the generated compounds, the failure and the strength of the compound or interface, respectively. Furthermore, the basic mechanical properties of the semi-finished product are analyzed. Because of defects at the interface the production process was optimized. This paper presents the results of further investigations about the compound quality and the possibilities to describe the quality based on the stresses during the process. A better quality and higher interface strength is achieved by adaptations of the die geometry. The analysis of the basic material properties evidences different yield stresses of the aluminum and the magnesium material and low residual stresses. The influence of the die on the yield stress of the materials will be explained in detail. The awareness of the parameters results in a combined model to describe the quality and the strength of the compound.

Recent Developments for the Production of Al-Mg Compounds

“…The quality of the compound can be determined by different tests, like visual inspection, ultrasonic testing, light microscopy analysis and dye penetration test. Thereby, the dye penetration test is an easy to use as well as standardized method and was used in all investigations [2][3][4][5][6]. A disadvantage of the dye penetration test is the destructive character of this method.…”

“…The manufacturing process was performed by hydrostatic co-extrusion [1][2][3][4][5][6]. The pre-assembled billet, consisting of an aluminum sleeve (AlMgSi1) and a magnesium core (AZ31), is extruded indirectly (force of hydrostatic medium) through a conic die.…”

“…Additionally applied layers of zinc or titanium between core and sleeve material did not further improve the compound quality. Kittner et al [2,3,4,5] analyzed the same material combination of AlMgSi1 and AZ31 by hydrostatic co-extrusion. By means of experimental and numerical investigations the main influencing parameters for a sufficient compound quality was determined.…”

A Fragmentation Criterion for the Interface of a Hydrostatic Extruded Al-Mg-Compound

“…Investigations with bending tests regarding the determination of the interfacial strength were performed in a wide temperature range from room temperature up to 400 • C [6,[17][18][19]. The loading condition and the specimen shape are designed such that failure occurs under a tensile normal stress.…”

Coextrusion and Mechanical Characterization of Aluminum Coated Mg-Profiles

“…Additionally, a quality model was developed which allows the prediction of compound failure [LEH10]. This model was enhanced later by Kittner et al [KIT11,KIT12]. The aim of the present work was an experimental study of the influence of the extrusion ratio R on the quality of diffusion layer formation at the interface Mg/Al.…”