Orientation influence on grain size effects in ultrafine-grained magnesium

The mechanical behavior of ultrafine-grained magnesium was studied by discrete dislocation dynamics (DDD) simulations. Our results show basal slip yields a strong size effect, while prismatic and pyramidal slips produce a weak one. We developed a new size–strength model that considers dislocation transmission across grain boundaries. Good agreement between this model, current DDD simulations and previous experiments was observed. These results reveal that the grain size effect depends on three factors: Peierls stress, dislocation source strength and grain boundary strength.

[1]  Julia R. Greer,et al.  Plasticity in small-sized metallic systems: Intrinsic versus extrinsic size effect , 2011 .

[2]  M. Barnett,et al.  Influence of grain size on the compressive deformation of wrought Mg–3Al–1Zn , 2004 .

[3]  P. Chung,et al.  The strength of binary junctions in hexagonal close-packed crystals , 2013 .

[4]  S. Papson,et al.  “Model” , 1981 .

[5]  Dierk Raabe,et al.  Dislocation interactions and low-angle grain boundary strengthening , 2011 .

[6]  S. Suwas,et al.  Room-temperature equal channel angular extrusion of pure magnesium , 2010 .

[7]  Michael D. Uchic,et al.  Contribution to size effect of yield strength from the stochastics of dislocation source lengths in finite samples , 2007 .

[8]  G. Rao,et al.  Grain boundary strengthening in strongly textured magnesium produced by hot rolling , 1982 .

[9]  K. Hemker,et al.  Stress-driven grain growth in ultrafine grained Mg thin film , 2013 .

[10]  J. Shin,et al.  Deformation behavior of magnesium in the grain size spectrum from nano- to micrometer , 2010 .

[11]  S. Miura,et al.  Effect of deformation temperature on Hall–Petch relationship registered for polycrystalline magnesium , 2004 .

[12]  Xiong Zhang,et al.  Thickness effects in polycrystalline thin films: Surface constraint versus interior constraint , 2011 .

[13]  M. Horstemeyer,et al.  Dislocation motion in magnesium: a study by molecular statics and molecular dynamics , 2009 .

[14]  Y. Estrin,et al.  The effect of grain refinement by warm equal channel angular extrusion on room temperature twinning in magnesium alloy ZK60 , 2005 .

[15]  U. Ramamurty,et al.  Micropillar and macropillar compression responses of magnesium single crystals oriented for single slip or extension twinning , 2014 .

[16]  J. A. Chapman,et al.  Effects of preferred orientation on the grain size dependence of yield strength in metals , 1963 .

[17]  Ian M. Robertson,et al.  TEM in situ deformation study of the interaction of lattice dislocations with grain boundaries in metals , 1990 .

[18]  Minsheng Huang,et al.  Size effect on the compressive strength of hollow micropillars governed by wall thickness , 2012 .

[19]  Athanasios Arsenlis,et al.  Enabling strain hardening simulations with dislocation dynamics , 2006 .

[20]  K. Xia,et al.  Effects of grain size on compressive behaviour in ultrafine grained pure Mg processed by equal channel angular pressing at room temperature , 2011 .

[21]  Z. Trojanová,et al.  Plastic and fatigue behaviour of ultrafine-grained magnesium , 2008 .

[22]  S. Joshi,et al.  Phenomenological crystal plasticity modeling and detailed micromechanical investigations of pure magnesium , 2012 .

[23]  W. Curtin,et al.  Discrete dislocation modeling of fracture in plastically anisotropic metals , 2013 .

[24]  K. T. Ramesh,et al.  Stochastic size-dependent slip-twinning competition in hexagonal close packed single crystals , 2014 .

[25]  Minsheng Huang,et al.  Toward a further understanding of intermittent plastic responses in the compressed single/bicrystalline micropillars , 2012 .

[26]  Blythe G. Clark,et al.  Influence of orientation on the size effect in bcc pillars with different critical temperatures , 2011 .

[27]  R. H. Wagoner,et al.  Dislocation and grain boundary interactions in metals , 1988 .

[28]  Minsheng Huang,et al.  Strengthening mechanism in micro-polycrystals with penetrable grain boundaries by discrete dislocation dynamics simulation and Hall-Petch effect , 2009 .

[29]  D. Dimiduk,et al.  Estimating the strength of single-ended dislocation sources in micron-sized single crystals , 2007 .

[30]  A. Minor,et al.  The nanostructured origin of deformation twinning. , 2012, Nano letters.

[31]  S. Agnew,et al.  Plastic anisotropy and the role of non-basal slip in magnesium alloy AZ31B , 2005 .

[32]  Marc A. Meyers,et al.  THE ONSET OF TWINNING IN METALS: A CONSTITUTIVE DESCRIPTION , 2001 .

[33]  J. El-Awady,et al.  Formation and slip of pyramidal dislocations in hexagonal close-packed magnesium single crystals , 2014 .

[34]  K. Hemker,et al.  Discerning size effect strengthening in ultrafine-grained Mg thin films , 2014 .