Irradiation-induced ? to ? SiC transformation at low temperature.

ABSTRACT: We observed that ?-SiC, neutron irradiated to 9?dpa (displacements per atom) at ?1440?°C, began transforming to ?-SiC, with radiation-induced Frank dislocation loops serving as the apparent nucleation sites. 1440?°C is a far lower temperature than usual ????? phase transformations in SiC. SiC is considered for applications in advanced nuclear systems, as well as for electronic or spintronic applications requiring ion irradiation processing. ?-SiC, preferred for nuclear applications, is metastable and undergoes a phase transformation at high temperatures (typically 2000?°C and above). Nuclear reactor concepts are not expected to reach the very high temperatures for thermal transformation. However, our results indicate incipient ????? phase transformation, in the form of small (~5-10?nm) pockets of ?-SiC forming in the ? matrix. In service transformation could degrade structural stability and fuel integrity for SiC-based materials operated in this regime. However, engineering this transformation deliberately using ion irradiation could enable new electronic applications.

SUBMITTER: Parish CM 

PROVIDER: S-EPMC5430638 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature