Screw dipoles acting as strong locks in Ni₃Al

Autor(en)

H. P. Karnthaler, C. Rentenberger, H. Yu

Abstrakt

Single crystalline specimens of L1₂ ordered binary Ni₃Al and Ni₃(Al,B) with single slip [1̄23] and multiple slip [001] orientations were deformed in compression within the anomalous temperature regime. In all cases the TEM investigations show that dipoles of locked screws are a dominant feature of the dislocation structure. This is of special interest since screw dipoles are not observed in disordered fcc structures. The results indicate that screws interact and form long sessile dipoles even when their heights is much larger (> factor of 10) than that given by the passing stress. The minimum height of the screw dipoles is about 16±4 nm and seems to be given when the interaction stress corresponds to the saturation stress. In the dipoles the locked screws are very difficult to unlock since the external stress is screened to a large extent. Therefore the deformation has to occur by the movement of edge segments. It is suggested that based on this exhaustion of the screws steady state conditions do not always apply on a local scale.

Organisation(en)

Physik Nanostrukturierter Materialien, Forschungsverbund Quantum Aspects of Space Time

Band

364

Seiten

315-320

Anzahl der Seiten

6

DOI

https://doi.org/10.1557/PROC-364-315

Publikationsdatum

1995

Peer-reviewed

Ja

ÖFOS 2012

103042 Elektronenmikroskopie, 103018 Materialphysik

ASJC Scopus Sachgebiete

Allgemeine Materialwissenschaften, Condensed Matter Physics, Mechanics of Materials, Mechanical Engineering

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/11d3efe6-2650-49fb-9ea4-b375cd979f0a