Micro-zone and macro mechanical behavior of SiCf/Si3N4 composite modified by intra-bundle matrix
Topic(s) : Material science
Co-authors :
Hao HAOHUI (FRANCE)Abstract :
SiC fiber reinforced Si3N4 matrix composite (SiCf/Si3N4) possesses high mechanical properties and excellent electromagnetic wave absorption performance, making it a promising candidate as the multifunctional composite for the application at high temperatures. The current research on the strengthening and toughening of this composite is rarely reported. Thus, an in-depth study of composite materials is imperative.
In this work, we studied the influence of intra-bundle matrix modification on micro-zone and macro mechanical behavior of the composites. The push-in test was conducted to measure the interfacial shear strength (IFSS). Traditionally, the interface model was established base on single fiber, the interfacial state of all fibers in the composites was the same, and the stress distribution in the fiber bundle was ignored. The Weibull modulus of IFSS was introduced to evaluate the uniformity of intra-bundle microstructure, leading to the different loading sharing efficiency of the entire fiber bundle. By establishing a stress transferring network model, the relationship between microstructure, micro-zone and macro mechanical properties of the composites was revealed from the perspective of failure probability.
In this work, the microstructure of the interfacial zone is optimized to improve the mechanical properties of SiCf/Si3N4 composite, and the relationship between micro-zone and macro mechanical behavior was revealed. For SiCf/Si3N4, the interphase destruction occurred during the Si3N4 deposition process, leading to the existence of discontinuous interphase in the outside of intra-bundle area. After incorporating SiBCN and SiC matrices into the fiber bundle, the BN interphase can be well protected, and the uniformity of the matrix microstructure within the fiber bundle is further enhanced. The fiber push-in test results shows that the IFSS of the composites were 60.6±38.3, 59.4±15.1 and 128.0±16.3 MPa, respectively, a higher IFSS makes the the load transferring efficiency of the interfacial zone be higher. And the Weibull modulus of the IFSS increases from 1.68 to 4.77 and 8.08, respectively, resulting in the higher load sharing efficiency in fiber bundle and the enhanced macro-mechanical properties. Especially after the incorporating SiC matrix into intra-bundle area, the higher IFSS also can be obtained, corresponding to the higher load transferring efficiency. The flexural strength and fracture toughness increase from 363±20 to 586±48 MPa, 19±1 to 32±1 MPa·m1/2, respectively.
In this work, we studied the influence of intra-bundle matrix modification on micro-zone and macro mechanical behavior of the composites. The push-in test was conducted to measure the interfacial shear strength (IFSS). Traditionally, the interface model was established base on single fiber, the interfacial state of all fibers in the composites was the same, and the stress distribution in the fiber bundle was ignored. The Weibull modulus of IFSS was introduced to evaluate the uniformity of intra-bundle microstructure, leading to the different loading sharing efficiency of the entire fiber bundle. By establishing a stress transferring network model, the relationship between microstructure, micro-zone and macro mechanical properties of the composites was revealed from the perspective of failure probability.
In this work, the microstructure of the interfacial zone is optimized to improve the mechanical properties of SiCf/Si3N4 composite, and the relationship between micro-zone and macro mechanical behavior was revealed. For SiCf/Si3N4, the interphase destruction occurred during the Si3N4 deposition process, leading to the existence of discontinuous interphase in the outside of intra-bundle area. After incorporating SiBCN and SiC matrices into the fiber bundle, the BN interphase can be well protected, and the uniformity of the matrix microstructure within the fiber bundle is further enhanced. The fiber push-in test results shows that the IFSS of the composites were 60.6±38.3, 59.4±15.1 and 128.0±16.3 MPa, respectively, a higher IFSS makes the the load transferring efficiency of the interfacial zone be higher. And the Weibull modulus of the IFSS increases from 1.68 to 4.77 and 8.08, respectively, resulting in the higher load sharing efficiency in fiber bundle and the enhanced macro-mechanical properties. Especially after the incorporating SiC matrix into intra-bundle area, the higher IFSS also can be obtained, corresponding to the higher load transferring efficiency. The flexural strength and fracture toughness increase from 363±20 to 586±48 MPa, 19±1 to 32±1 MPa·m1/2, respectively.