The effect of the pyrolytic carbon(PyC)interface thickness on the heat-stability of CansasⅡSiC_(f)/SiC composites under Ar up to 1500℃was studied in detail.After the heat treatment at 1500℃for 50 h,the interface bo...The effect of the pyrolytic carbon(PyC)interface thickness on the heat-stability of CansasⅡSiC_(f)/SiC composites under Ar up to 1500℃was studied in detail.After the heat treatment at 1500℃for 50 h,the interface bonding strength of the thin interface(about 200 nm)decreases from 74.4 to 20.1 MPa(73.0%),while that of the thick interface(about 2μm)declines from 7.3 to 3.2 MPa(52.7%).At the same time,the decline fraction of strength of the composites with the thin interface is 12.1%,less than that with the thick interface(42.0%).The fiber strength also decreases after heat treatment,which may be due to the significant growth ofβ-SiC grains and critical defects.The different heat-stability of the interface with the thin and thick thickness might be related to the inconsistency of the degree of the graphitization of PyC.Compared with the composites with the thick interface,the composites with the thin interface remained higher tensile strength after heat treatment due to the better interface bonding strength.The interface with strong bonding strength could protect the fiber by postponing the decomposition of amorphous phases SiC_(x)O_(y) and hindering the generation of fiber defects.展开更多
The longitude tensile properties of 3-Dimension-4-directional（3D-4d） braided C/Si C composites（CMCs） were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In...The longitude tensile properties of 3-Dimension-4-directional（3D-4d） braided C/Si C composites（CMCs） were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In micro-scale, the tensile properties of fiber tows which involves matrix cracking, interfacial debonding, and fiber failure are studied. The unit-cell scale model can reflect the braided structure and simulate the tensile properties of 3D-4d CMCs by introducing the tensile properties of fiber tows into it. Quasi-static tensile tests of 3D-4d braided CMCs were performed on a PWS-100 test system. The predicted tensile stressstrain curve by the double scale model is in good agreement with that of the experimental results.展开更多
基金Funded by the National Science and Technology Major Project(No.2017-IV-0005-0042)the China Postdoctoral Science Foundation(No.2021M691566)。
文摘The effect of the pyrolytic carbon(PyC)interface thickness on the heat-stability of CansasⅡSiC_(f)/SiC composites under Ar up to 1500℃was studied in detail.After the heat treatment at 1500℃for 50 h,the interface bonding strength of the thin interface(about 200 nm)decreases from 74.4 to 20.1 MPa(73.0%),while that of the thick interface(about 2μm)declines from 7.3 to 3.2 MPa(52.7%).At the same time,the decline fraction of strength of the composites with the thin interface is 12.1%,less than that with the thick interface(42.0%).The fiber strength also decreases after heat treatment,which may be due to the significant growth ofβ-SiC grains and critical defects.The different heat-stability of the interface with the thin and thick thickness might be related to the inconsistency of the degree of the graphitization of PyC.Compared with the composites with the thick interface,the composites with the thin interface remained higher tensile strength after heat treatment due to the better interface bonding strength.The interface with strong bonding strength could protect the fiber by postponing the decomposition of amorphous phases SiC_(x)O_(y) and hindering the generation of fiber defects.
基金Funded by the National Basic Research Program of Chinathe National Natural Science Foundation of China(51675266)+3 种基金the Aeronautical Science Foundation of China(2014ZB52024)the Fundamental Research Funds for the Central Universities(NJ20160038)the Jiangsu Innovation Program for Graduate Education(CXLX13_165)the Fundamental Research Funds for the Central Universities
文摘The longitude tensile properties of 3-Dimension-4-directional（3D-4d） braided C/Si C composites（CMCs） were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In micro-scale, the tensile properties of fiber tows which involves matrix cracking, interfacial debonding, and fiber failure are studied. The unit-cell scale model can reflect the braided structure and simulate the tensile properties of 3D-4d CMCs by introducing the tensile properties of fiber tows into it. Quasi-static tensile tests of 3D-4d braided CMCs were performed on a PWS-100 test system. The predicted tensile stressstrain curve by the double scale model is in good agreement with that of the experimental results.
