Abstract
A Ni-based solder BNi-5 was adopted as the repair agent to repair the prefabricated defects on the car-bon/carbon(C/C)composites.The effects of different heat-treatment(HT)temperatures and pre-oxidation on the chemical composition,microstructure,and mechanical behavior of the repaired C/C composites were investigated,and the repair mechanism was studied by finite element analysis methods.The repair agent and C/C composites were tightly bonded through mechanical interlocking and chemical reactions,and the flexural properties of the damaged C/C composites were significantly improved after repair.The products at the interface formed a gradient distribution structure of the thermal expansion coefficient when the HT temperature was 1300 ℃,which is beneficial to relieve the residual thermal stress at the interface.Meanwhile,the porosity of the surface of the C/C composites was higher after pre-oxidation,which led to more diffusion channels for the repair agent and enhanced the interface bonding ability.The flexural strength was the highest with a recovery rate of 85.2％when the C/C composites were pre-oxidized at 600 ℃ and the HT temperature was 1300 ℃.This work provides a strategy for the engineering application of the damage repair of C/C composites.
基金项目
National Key R&D Program of China(2021YFA0715800)
National Key R&D Program of China(2021YFA0715803)
Science Center for Gas Turbine Project(P2021-A-Ⅳ-003-001)
National Natural Science Foundation of China(52125203)
NETL
NSTL
万方数据