Effect of pre-fatigue on bending behavior of 2.5D C/C composites

Release time:2021-07-16

DOI number:10.1016/j.msea.2016.11.055

Affiliation of Author(s):中南大学

Journal:Materials Science & Engineering A

Key Words:Bending strength，Pre-fatigue，Stress level，Interface

Abstract:This study in vestigates the in fluence of pre-fatigue on the bending behavior of needle-punctured 2.5D C/C composites with density between 1.75 and 1.80g/cm3 prepared by chemical vapor deposition(CVD). Three point bending pre-fatigue tests are carried out under applied stress/static flexural strength ratio of 60%, 70%, 80% and 90% up to one million cycles. The results show that except for the 60% sample, flexural bending strength of most samples subjected to pre-fatigue is improved significantly compared with that without pre-fatigue. Detailed investigation indicates that the subsequent bending behavior of sample is closely related to both stress level in pre-fatigue and the resultant microstructure. Under low stress level(60–70%) during pre-fatigue, the composite is characterized by aplasticde formation and as lighten hancement of bending strength ascribed to the weakened fiber/matrix interface after fatigue. After pre-fatigue with high stress level(80–90%), the composite demonstrates brittle failure mode but much higher residual strengths during subsequent bending test. The reason for this is ascribed to the variation of the microstructure in fiber/matrix interface during the pre-fatigue, which strongly affects the subsequent mechanical responses.

Indexed by:Article

Discipline:Engineering

First-Level Discipline:Materials Science and Engineering

Document Type:J

Volume:682

Page Number:290-295

Translation or Not:no

Date of Publication:2017-01-17

Included Journals:SCI