Exploring the transfer of plasticity across Laves phase interfaces in a dual phase magnesium alloy

• Published in: Materials & Design 2021-04, Vol.202, p.109572, Article 109572
• Main Authors: Guénolé, Julien, Zubair, Muhammad, Roy, Swagata, Xie, Zhuocheng, Lipińska-Chwałek, Marta, Sandlöbes-Haut, Stefanie, Korte-Kerzel, Sandra
• Format: Article
• Language: English
• Subjects: Atomistic simulations; Condensed Matter; Dislocation; Indentation; Intermetallic; Materials and structures in mechanics; Materials Science; Mechanics; Mechanics of materials; Physics; Scanning electron microscopy
• ISSN: 0264-1275; 0261-3069; 1873-4197; 0264-1275
• DOI: 10.1016/j.matdes.2021.109572

The mechanical behaviour of MgAl alloys can be largely improved by the formation of an intermetallic Laves phase skeleton, in particular the creep strength. Recent nanomechanical studies revealed plasticity by dislocation glide in the (Mg,Al)2Ca Laves phase, even at room temperature. As strengthening skeleton, this phase remains, however, brittle at low temperature. In this work, we present experimental evidence of slip transfer from the Mg matrix to the (Mg,Al)2Ca skeleton at room temperature and explore associated mechanisms by means of atomistic simulations. We identify two possible mechanisms for transferring Mg basal slip into Laves phases depending on the crystallographic orientation: a direct and an indirect slip transfer triggered by full and partial dislocations, respectively. Our experimental and numerical observations also highlight the importance of interfacial sliding that can prevent the transfer of the plasticity from one phase to the other. [Display omitted] •Co-deformation of Mg-Laves phase composites shows cracking, slip deformation and interfacial sliding.•The active co-deformation mechanism depends on the interfacial orientation.•Slip transfer into the Laves phase occurs on prismatic and basal planes.•Interfacial sliding is favoured by matrix dislocations absorbed at the interface.