Fatigue of Magnesium Alloys

Abstract

Magnesium alloys show a high specific strength and are therefore increasingly used for light‐weight constructions in transportation industry.[1,2] To predict the behaviour of the material under the influence of cyclic loading it is vital to understand the fatigue behaviour of magnesium alloys. Only when understood properly, it is possible to fully apply the potential weight reduction by using magnesium alloys. A very important aspect in fatigue of magnesium alloys is the influence of a corrosive media and elevated temperatures, of which both are relevant in automotive applications. These two factors tend to have deleterious effects on magnesium alloys and therefore also have to be considered in investigations on the fatigue behaviour of magnesium alloys.

The effect of thermo-mechanical processing on the structure, static mechanical properties and fatigue behaviour of pure Mg

“…26 Due to such limitations, complex dislocation structures are rather unlikely in magnesium under cyclic loading. 24,27 In the case of pure Mg, cyclic hardening is expected as has already been proved in 28 .…”

Fatigue Endurance of Magnesium Alloys

“…This cyclic hardening effect happens within approximately the first 10 000 cycles. A generalization of the cyclic behaviour of magnesium alloys is not possible due to the differences in microstructure of the alloy systems and their heat treatment (Potzies & Kainer, 2004). Like in the other metals, fatigue cracks in magnesium alloys also initiate at slip bands developed by cyclic micro-plastic deformation.…”

“…Additionally, high crack tip driving forces tend to promote crack propagation through the Al 12 Mg 17 phase, while lower loads assist crack propagation through the primary alpha-Mg grains. The crack growth is additionally assisted by the connection of different microcracks or -especially in material with casting defects -cracks, which developed between pores or microshinkage (Potzies & Kainer, 2004). Concerning the crack propagation rate, magnesium and its alloys in general, show a very low fracture toughness, which therefore promotes a higher crack propagation rate than in other light metal.…”

“…shotpeening, deep-rolling) can be used to modify the edge layer. The increased near-surface dislocation density and the implemented compressive residual stresses significantly reduce the crack propagation rate, increasing the fatigue lives although the crack initiation is accelerated due to the increased surface roughness (Potzies & Kainer, 2004). Fatigue crack propagation of long cracks is customarily divided in three regimes.…”

Ab initio study of structural stability and electronic properties of Ti1-xMgxCr2 and TiMgxCr2-x laves phase

“…In this work, we propose to incorporate mg in TiCr 2 , since Mg-alloys are widely used in structural application, automobile, electronics, aerospace, hydrogen storage and other industries. Mg-alloys have very interesting and advantageous properties which include outstanding strength to weight ratio (low density), high stiffness to weight ratio; especially in wrought products, low machining cost, high creep resistance, ease of founding large and complex casting, good weldability, very good hot forming properties, good corrosion resistance properties, high storage capacity of hydrogen, good dimensional stability [13][14][15] Thus, the study for the first time attempts to systematically explore the stability and the structural properties of TiCr 2 and TiMgCr 2 and after to investigate the electronic properties through electronic density of states. We have used first-principles density functional calculation based on the pseudo-potential method within the generalized gradient approximation (GGA).…”