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Deformation-induced structural transition in body-centred cubic molybdenum
11] Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China [2] Beijing National Center for Electron Microscopy, Tsinghua University, Beijing 100084, China.
Nature Communications
|March 8, 2014
Summary
Pure molybdenum, a refractory metal, undergoes a surprising structural transformation during plastic deformation. This study reveals a novel deformation mechanism involving body-centered cubic to face-centered cubic transitions under high stress.
Area of Science:
- Materials Science
- Metallurgy
- Solid-State Physics
Background:
- Molybdenum (Mo) is a refractory metal with a stable body-centered cubic (BCC) structure.
- Plastic deformation through structural transitions is common in alloys and ceramics, but not previously reported for pure Mo.
Purpose of the Study:
- To investigate and demonstrate a novel plastic deformation mechanism in pure molybdenum.
- To characterize the structural transformations occurring at crack tips during high-stress deformation.
Main Methods:
- In-situ straining experiments within a transmission electron microscope (TEM).
- High-resolution imaging and nanodiffraction techniques.
- Molecular dynamics simulations.
Main Results:
- Observed a reversible structural transformation from BCC to face-centered cubic (FCC) at crack tips.
- FCC domains reverted to BCC with a specific lattice rotation (54.7°).
- Achieved significant tensile strain (~15.4%) during the transformation process.
Conclusions:
- Pure molybdenum exhibits a unique deformation mechanism involving BCC-FCC-BCC structural transitions under high stress.
- The FCC phase represents a metastable state, validated by experimental and simulation data.
- This finding expands the understanding of deformation mechanisms in elemental metals.
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