A dual-phase microstructural approach to damage and fracture of Ti₃SiC₂/SiC joints

Journal Article · 05 December 2017 · Journal of Nuclear Materials

DOI: https://doi.org/10.1016/j.jnucmat.2017.11.054 · OSTI ID:1411874

Nguyen, Ba Nghiep ^[1]; Henager, Charles H. ^[1]; Kurtz, Richard J. ^[1]

---

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

We investigate the microcracking mechanisms responsible for Ti₃SiC₂/SiC joint damage observed at the macroscopic scale after neutron irradiation experiments in detail. A dual-phase microstructural approach to damage and fracture of Ti₃SiC₂/SiC joints is developed that uses a finely discretized two-phase domain based on a digital image of an actual microstructure involving embedded Ti₃SiC₂ and SiC phases. The behaviors of SiC and Ti₃SiC₂ in the domain are described by the continuum damage mechanics (CDM) model reported in Nguyen et al., J. Nucl. Mater., 2017, 495:504–515. This CDM model describes microcracking damage in brittle ceramics caused by thermomechanical loading and irradiation-induced swelling. The dual-phase microstructural model is applied to predict the microcracking mechanisms occurring in a typical Ti₃SiC₂/SiC joint subjected to heating to 800 °C followed by irradiation-induced swelling at this temperature and cooling to room temperature after the applied swelling has reached the maximum swelling levels observed in the experiments for SiC and Ti₃SiC₂. The model predicts minor damage of the joint after heating but significant microcracking in the SiC phase and along the boundaries between SiC and Ti₃SiC₂ as well as along the bonding joint during irradiation-induced swelling and cooling to room temperature. Our predictions qualitatively agree with the limited experimental observations of joint damage at this irradiation temperature.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 1411874
• Report Number(s): PNNL-SA--128595; PII: S0022311517312564
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Vol. 499; ISSN 0022-3115
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English