Tuning ideal tensile strengths and intrinsic ductility of bcc refractory alloys

An important theoretical ductility criterion for group V and VI metal-based refractory alloys in body-centered cubic (bcc) lattices is the mechanical failure mode of their perfect crystals under tension along the weakest direction [100]. Pure Mo and W fail by cleavage and are deemed intrinsically br...

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Bibliographic Details
Published in:Physical review letters 2014-03, Vol.112 (11), p.115503-115503
Main Authors: Qi, Liang, Chrzan, D C
Format: Article
Language:English
Subjects:
Alloys - chemistry
Computer Simulation
Crystallization
Models, Molecular
Molybdenum - chemistry
Niobium - chemistry
Tensile Strength
Thermodynamics
Tungsten - chemistry
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Summary:An important theoretical ductility criterion for group V and VI metal-based refractory alloys in body-centered cubic (bcc) lattices is the mechanical failure mode of their perfect crystals under tension along the weakest direction [100]. Pure Mo and W fail by cleavage and are deemed intrinsically brittle. However, first-principles calculations show that alloying with group IV or V transition metals can transform these materials into ones that display intrinsically ductile behavior, failing in shear under [100] tension. Remarkably, this transition can be understood as an electron filling effect with the intrinsically ductile response the manifestation of a Jahn-Teller distortion.
ISSN:1079-7114
DOI:10.1103/PhysRevLett.112.115503