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 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.
Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
Liang
L
Qi
Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
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D000497:Alloys / Q000737:chemistry*; D003198:Computer Simulation; D003460:Crystallization; D008958:Models, Molecular; D008982:Molybdenum / Q000737:chemistry*; D009556:Niobium / Q000737:chemistry; D013718:Tensile Strength; D013816:Thermodynamics; D014414:Tungsten / Q000737:chemistry*
D000497:Alloys; D009556:Niobium; D008982:Molybdenum; D014414:Tungsten