TY - CHAP

T1 - Microstructure-Oriented Fatigue Crack Propagation in Two Cast Mg–Al–Ba–Ca Alloys

AU - Maier, Petra

AU - Wolfram, Benjamin

AU - Roggelin, Jens

AU - Hort, Norbert

N1 - Publisher Copyright: © The Minerals, Metals & Materials Society 2025.

PY - 2025

Y1 - 2025

N2 - Two cast Mg–Al–Ba–Ca alloys, DieMag633 and DieMag844, are the focus of this study. Their microstructureMicrostructure consists of a eutectic Ca-rich structure, the lamellar Al2Ca, and of a hard, compact and brittle interdendritic Ba-rich phase, the Mg21Al3Ba2 phase. Both phases have a much higher hardness than the α-Mg matrix and strongly influence the crack propagationCrack propagation under quasi-static and fatigueFatigue loading. Mostly interdendritic crack propagationCrack propagation has been found—the crack growth follows the coherent interdentritic network of second phases. Transgranular cracking within the compact Ba-rich phase is very pronounced, showing many microcracks within this phase. The phases strain harden in a different amount. Transdendritic cracks are found only under cyclic fatigueFatigue loading, and the cracks transit from the second phases into the α-Mg dendritesDendrites. The lower crack growth rate and the stress increase at the interface to the dendritesDendrites seem responsible for the transdentritc crack propagationCrack propagation. The influence of the chemical composition of the alloying elements and the fatigueFatigue stress ratios are discussed.

AB - Two cast Mg–Al–Ba–Ca alloys, DieMag633 and DieMag844, are the focus of this study. Their microstructureMicrostructure consists of a eutectic Ca-rich structure, the lamellar Al2Ca, and of a hard, compact and brittle interdendritic Ba-rich phase, the Mg21Al3Ba2 phase. Both phases have a much higher hardness than the α-Mg matrix and strongly influence the crack propagationCrack propagation under quasi-static and fatigueFatigue loading. Mostly interdendritic crack propagationCrack propagation has been found—the crack growth follows the coherent interdentritic network of second phases. Transgranular cracking within the compact Ba-rich phase is very pronounced, showing many microcracks within this phase. The phases strain harden in a different amount. Transdendritic cracks are found only under cyclic fatigueFatigue loading, and the cracks transit from the second phases into the α-Mg dendritesDendrites. The lower crack growth rate and the stress increase at the interface to the dendritesDendrites seem responsible for the transdentritc crack propagationCrack propagation. The influence of the chemical composition of the alloying elements and the fatigueFatigue stress ratios are discussed.

KW - Crack propagation

KW - Dendrites

KW - Fatigue

KW - Interdendritic second phases

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=86000450580&partnerID=8YFLogxK

U2 - 10.1007/978-3-031-81061-9_10

DO - 10.1007/978-3-031-81061-9_10

M3 - Article in conference proceedings

AN - SCOPUS:86000450580

SN - 978-3-031-81060-2

T3 - Minerals, Metals and Materials Series

SP - 87

EP - 96

BT - Magnesium Technology 2025

A2 - Tolnai, Domonkos

A2 - Palumbo, Aaron

A2 - Leonard, Aeriel

A2 - Neelameggham, Neale R.

PB - Springer Science and Business Media Deutschland GmbH

T2 - Magnesium Technology Symposium, 2025, held as part of the TMS Annual Meeting and Exhibition, TMS 2025

Y2 - 23 March 2025 through 27 March 2025

ER -