The electronic origin of strengthening and ductilizing magnesium by solid solutes

Shang

et al. 2015

JOM

The current work aims to reveal the effects of solute atoms (TM = Ag, Zn, and Zr) on the age hardening of Mg-Gd-based alloys via the density functional theory and electron work function (EWF) approaches. The 10H LPSO phases of Mg-Gd-TM alloys are selected as the model case due to the improved strength and ductility such long periodic stacking ordered precipitates (LPSOs) offer. The CALPHAD-modeling method is applied to predict the EWF in the ternary Mg-Gd-TM alloys. The obtained EWFs of these Mg alloys are shown to match well with previous experimental and theoretical results. Moreover, the variation of EWF in the ternary Mg-Gd-TM alloys is attributed to the structure contribution [i.e., the formation of face-centered cubic (fcc)-type fault layers] and the chemical effect of solute atoms (i.e., electron redistributions). With the knowledge of bonding charge density between the solute and solvent atoms, the present work provides insight into the correlations between the EWF and hardness of Mg-Gd-TM alloys.

Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Crystallographic Structures and Computational Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

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Solid-Solution Hardening in Mg-Gd-TM (TM = Ag, Zn, and Zr) Alloys: An Integrated Density Functional Theory and Electron Work Function Study

Shang

et al. 2015

JOM

Advances in Materials Science and Engineering

“…These processes hinder dislocation propagation and finally lower the alloys' plastic flow ability. This gives rise to increased yield strength proportional to the solute concentration in Mg-Li alloys [31,32]. In a study by Chiang et al [1], grain refining and strengthening of Mg-Li-Al-Zn-RE alloys by solid solution treatment followed by water quenching were carried out.…”

Section: Numbermentioning

confidence: 99%

Strengthening Mechanisms of Magnesium-Lithium Based Alloys and Composites

Muga

Zhang

2016

Mg-Li based alloys are widely applied in various engineering applications. The strength of these alloys is modified and enhanced by different strengthening mechanisms. The strengthening mechanisms of these alloys and their composites have been extensively studied during the past decades. Important mechanisms applied to strengthening the alloys include precipitation strengthening, solution strengthening, grain and subgrain strengthening, and dislocation density strengthening. Precipitation and solution strengthening mechanisms are strongly dependent on composition of the alloys and thermal treatment processes, whereas grain and subgrain and dislocation density strengthening mechanisms majorly depend on thermomechanical processing. In this paper, recent studies on conventional processes for the strengthening of Mg-Li based alloys are summarized as they are critical during the alloys design and processing. Main strengthening mechanisms are objectively reviewed, focusing on their advantages and drawbacks. These can contribute to enhancing, initiating, and improving future researches for alloys design and suitable processing selection.

First‐Principles Calculations and a Theoretical Model for Predicting Stacking Fault Energies in Binary Magnesium Alloys

Qiu

Song

2023

Adv Eng Mater

Comprehensive first‐principles density functional theory (DFT) calculations are conducted to study the effects of solutes on the stacking fault energies (SFEs) for basal, prismatic, and pyramidal slip systems in binary magnesium alloys. The two main aspects prescribing the solute effect on SFE are elucidated to be mechanical and electronic in nature, respectively, and critically assessed. On the basis of the misfit volume and d‐electrons, these two aspects are then quantified and subsequently a predictive model of the solute effect on the SFE is developed, with good agreement achieved between the model prediction and DFT results. Herein, important mechanistic insights and predictivity critical for rational design of Mg alloys of enhanced mechanical properties are provided.