Intermetallic compounds and choice of alloying elements for the manufacture of thixomolded creepresistant magnesium alloys

Abstract

This study aims at finding ways to improve the service properties of state-of-the-art creepresistant Mg alloys for Thixomolding and minimise production problems. In doing so, microalloying with Si, Zn, Sr, Li, C, Ba and Bi, as well as the addition of rare earths is a viable solution.

Feasibility study on utilizing carbon dioxide during the processing of Mg–Al alloys

“…In the Mg + 5 wt.%Al + CO 2 alloy, the formation of Al 4 C 3 phase did not contribute to any change in the density. The slight decrease in the CTE value of the Mg + 5 wt.%Al + CO 2 alloy when compared to that processed without CO 2 is due to the formation of Al 4 C 3 phase that has lower CTE value (∼5 × 10 −6 K −1 , value reported by Besterci et al (2009)), which forms at the expense of the Mg 17 Al 12 phase (CTE ∼ 29.310 −6 K −1 , value given by Goryany and Mauk (2007)). …”

Thermodynamic reassessment of the La-Mn system

“…is the excess Gibbs energy which is described by the RedlichKister (R-K) polynomial [27]: (3) in which is the j th R-K parameter of liquid phase and can be expressed as . The coefficients a j and b j (j=0, 1, 2) are the parameters to be optimized.…”

“…The addition of a small amount of Mn in Mg-based alloys yields an improvement of corrosion resistance and enhancement of grain refinement [2]. While a small addition of rare earth elements such as lanthanum, cerium or neodymium will lead to attractive properties of Mg-based alloys [3], such as good anti-corrosion [4,5], high tensile strength [6], and excellent weld ability [7]. To optimize alloy composition and efficiently develop the Mg-based alloys with desirable properties, knowledge of phase equilibria and thermodynamic properties in the La-Mn system is indispensable.…”

Effects of Melt Vibration During Solidification on the Mechanical Property of Mg-Al-Zn Alloy

“…These could be explained that the structures of the Mg-Al-Zn alloys consist of a solid solution and the intermetallic compound Mg 17 Al 12 (β phase) at the grain boundaries the quantity and character of these intermetallic compounds greatly influence the pouring characteristics and mechanical properties of the component. Intermetallic compounds affect the plasticity of the alloys in a semi-solid and solid state [16]. The compound Mg 17 Al 12 , as the phase solidifying last, fills interdendritic cavities and thus influenc es flowability, shrinkage, porosity, and the development of cracks, [17].…”