Exploring the elastic and electronic properties of chromium molybdenum diboride alloys

•First principle study using density functional theory.•The structural properties of Cr1−xMoxB2 diboride where explored using structural search methods.•The mechanical strength of Cr1−xMoxB2 maximizes when x = 50%, with Vickers hardness reaching 27 GPa.•Correlations between elastic constants, mechan...

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Bibliographic Details
Published in:Journal of alloys and compounds 2021-06, Vol.866 (C), p.158885, Article 158885
Main Authors: Dovale-Farelo, Viviana, Tavadze, Pedram, Verstraete, Matthieu J., Bautista-Hernández, Alejandro, Romero, Aldo H.
Format: Article
Language:English
Subjects:
Ab initio calculations
Bonding strength
CECI
Chemical bonds
Chemistry
Chromium base alloys
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
Crystal structure
Diamond pyramid hardness
Elastic properties
Electronic properties
First principles
Heat capacity
High-temperature alloys
INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Interlayers
Magnetic properties
MATERIALS SCIENCE
Mathematical analysis
Mechanical properties
Metallurgy & metallurgical engineering
Molybdenum
Phonons
Physical, chemical, mathematical & earth Sciences
Physics
Physique
Physique, chimie, mathématiques & sciences de la terre
Thermal expansion
Thermodynamic properties
Transition metal alloys and compounds
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Summary:•First principle study using density functional theory.•The structural properties of Cr1−xMoxB2 diboride where explored using structural search methods.•The mechanical strength of Cr1−xMoxB2 maximizes when x = 50%, with Vickers hardness reaching 27 GPa.•Correlations between elastic constants, mechanical properties and hardness have been discussed.•Crystal orbital Hamilton populations curves were used for chemical bonding analysis. We perform first-principles calculations to study the structural, mechanical, thermal, electronic, and magnetic properties of Cr1−xMoxB2 for x = 0.25, 0.33, 0.50, 0.67 and 0.75. Based on structural search methods, we determine the ground-state structure for each concentration. The ternaries are either monoclinic (x = 0.25, 0.75) or trigonal (x = 0.33, 0.50, 0.67). The calculated mechanical properties reveal that the strength of Cr1−xMoxB2 is maximized for x = 0.50. Cr0.5Mo0.5B2 exhibits excellent mechanical properties (B = 298 GPa, Y = 558 GPa, G = 235 Gpa, ν = 0.19, Hv =27 GPa), surpassing those of β-MoB2 at a lower cost. All of these ternaries are hard alloys with Vickers hardness greater than 24 GPa. Chemical bonding analysis demonstrates that the strength of the new compounds is related to the alternating planar and buckled B-B layers, as well as the strong TM-B bonds. The enhanced strength of Cr0.5Mo0.5B2 is a consequence of the high density of strong interlayer Cr-Mo metallic bonds around the Fermi level.
ISSN:0925-8388
1873-4669
1873-4669
DOI:10.1016/j.jallcom.2021.158885