The Effect of Specimen Size and Test Procedure on the Creep Behavior of ME21 Magnesium Alloy

Abstract

Lightweight constructions and materials offer the opportunity to reduce CO2 emissions in the transport sector. As components in vehicles are often exposed to higher temperatures above 40% of the melting temperature, there is a risk of creep. The creep behavior usually is investigated based on standard procedures. However, lightweight constructions frequently have dimensions not adequately represented by standardized specimen geometries. Therefore, comparative creep experiments on non-standardized miniature and standardized specimens are performed. Due to a modified test procedure specified by a miniature creep device, only the very first primary creep stage shows a minor influence, but subsequently, no effect on the creep process is detected. The creep behavior of hot extruded and heat treated ME21 magnesium alloy is investigated. It is observed that the creep parameters determined by the miniature and standard creep tests are different. As the deviations are systematic, qualitatively, evidence of the creep behavior is achieved. The creep parameters obtained, and particularly the creep strain and the strain rate, show a higher creep resistance of the miniature specimen. An initial higher number of twinned grains and possible multiaxiality in the gauge volume of the miniature specimen can be responsible.

Hot Deformation Behavior, Processing Maps and Microstructural Evolution of the Mg-2.5Nd-0.5Zn-0.5Zr Alloy

“…The geometry dislocation calculation method was that described in Refs. [ 6 , 15 ]. The gradual change from blue to red in the KAM maps shows that the local directional deviation was gradually increasing.…”

“…They have been widely used in aerospace, automotive, electronics, medical devices and other industries [ 2 , 3 , 4 ]. The mechanical and structural properties of Mg alloys and their response to stresses are currently a hot topic [ 5 , 6 , 7 ]. Many studies have shown that rare earth (RE) elements could significantly strengthen Mg alloys [ 8 , 9 , 10 , 11 , 12 ].…”

Properties of Transition Metals and Their Compounds at Extreme Conditions

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