Microstructure evolution in copper under severe plastic deformation detected by in situ X-ray diffraction using monochromatic synchrotron light

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 503; no. 1; pp. 10 - 13
• Main Authors: Kilmametov, A.R., Vaughan, G., Yavari, A.R., LeMoulec, A., Botta, W.J., Valiev, R.Z.
• Format: Journal Article Conference Proceeding
• Language: English; Russian
• Published: Kidlington Elsevier B.V 15.03.2009; Elsevier
• Subjects: Chemical and Process Engineering; Chemical Sciences; Engineering Sciences; High-pressure torsion; Material chemistry; Severe plastic deformation; Synchrotron light; Ultrafine-grained copper; X-ray diffraction; X-ray diffraction; Severe plastic deformation; Ultrafine-grained copper; Synchrotron light; High-pressure torsion
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2008.11.023

Microstructure evolution in severely deformed Cu has been investigated using high-energy synchrotron light during in situ high-pressure torsion (HPT) at room temperature. Relative changes in broadening of Bragg peaks and crystal lattice expansion were studied in the loading–unloading regime of torsion straining. Experimental results revealed fast relaxation (on the order of hundred of seconds) that occurred due to annihilation of HPT-induced crystal lattice defects, which were generated directly during deformation. The kinetics of relaxation is probably diffusion-controlled; therefore, the enhanced diffusivity can be explained by extremely high excess vacancy concentration, which is usually achieved at thermal equilibrium near the melting point.