Investigation of flexural behavior and microstructure of Amosic-3 silicon carbide composites under neutron irradiation

SiC/SiC composites prepared by the chemical vapor infiltration process have been investigated under neutron irradiation at approximately 40 °C to doses of 0.03 and 0.2 displacements per atom (dpa) in the China Mianyang Research Reactor. Irradiation effects were characterized by three-point flexural tests, micro-Raman spectra and transmission electron microscopy observations. The results demonstrated that the ultimate flexural stress and flexural modulus decreased remarkably with irradiation doses up to 0.2 dpa. Micro-Raman spectra of the Amosic-3 fiber and SiC matrix revealed that both reduction of Si–C bonds and enhancement of Si–Si bonds were increased from 0.03 to 0.2 dpa. Microstructural observation revealed that the Amosic-3 fiber suffered from grain fragmentation and amorphization. Meanwhile, matrix amorphization is generated preferentially at the site of stacking fault structures. In addition, it suggested that in the current work, up to 0.2 dpa, full amorphization was not completed in the Amosic-3 fiber, PyC and SiC matrix.