摘要
利用化学气相渗透(chemical vapour infiltration,CVI)在SiC纤维束中引入PyC(pyrolytic carbon,热解碳)界面和(PyC/SiC)_(3)多层界面,并分别在1050℃和1250℃下对含PyC界面SiC纤维束、1050℃下对含(PyC/SiC)_(3)3多层界面纤维束进行Si C基体增密,制备出不同界面类型和基体结构的SiC_(f)/SiC(continuous SiC fiber reinforced SiC matrix)Mini复合材料。研究界面类型和基体致密化温度对SiC_(f)/SiCMini复合材料微观结构和拉伸断裂行为的影响。结果表明,SiC_(f)/SiC Mini复合材料内部纤维和基体间的界面清晰,界面厚度约300 nm。1050℃致密化的PyC界面SiC_(f)/SiCMini复合材料的抗拉强度为174MPa,脱黏主要发生在基体与界面之间。而(PyC/SiC)_(3)3多层界面SiC_(f)/SiC Mini复合材料抗拉强度达到540 MPa,脱黏主要发生在亚层与亚层之间。PyC界面SiC_(f)/SiC Mini复合材料随基体致密化温度升高,S C基体从细小多孔的针状转变为粗大致密的层片状,晶粒尺寸和结晶度显著提高。1250℃致密化的复合材料的抗拉强度为309 MPa,呈典型的脆性断裂特征。
Pyrolytic carbon (PyC) interface and (PyC/SiC)_(3)multi-layer interfaces were introduced into SiC fiber bundles by chemical vapour infiltration (CVI). After densification of SiC matrix in SiC fiber bundles containing PyC interface at1 050 ℃ and 1250 ℃, and in SiC fiber bundles containing (PyC/SiC)_(3)multilayer interface at 1 050 ℃, SiC/Si C Mini composites with different interface types and different matrix structures were obtained. The microstructure and tensile fracture behavior of the as-prepared SiC_(f)/SiC minicomposites were studied. The results show that a clear interface with the thickness of about 300 nm is introduced successfully between the inner fiber and the SiC matrix. After densification at1 050 ℃, the tensile strength of the SiC_(f)/SiC Mini composite with PyC interface is 174 MPa, with the debonding mainly occurring between the SiC matrix and the interface. While the tensile strength of SiC_(f)/SiC Mini composites with(PyC/SiC)_(3)multilayer interface reaches 540 MPa, with the debonding mainly occurring between the sublayer of the multilayer. As the densification temperature increases, the SiC matrix of the SiC/Si C Mini composites changes from fine,porous needle-like to coarse, dense lamellar, with the grain size and crystallinity increaseing significantly. The tensile strength of the composites obtained at 1 250 ℃ is 309 MPa, showing typical brittle fracture characteristics.
作者
王铎
陈招科
何宗倍
张瑞谦
熊翔
WANG Duo;CHEN Zhaoke;HE Zongbei;ZHANG Ruiqian;XIONG Xiang(Science and Technology on High Strength Materials Laboratory,Central South University,Changsha 410083,China;Science and Technology on Reactor Fuel and Materials Laboratory,Nuclear Power Institute of China,Chengdu 610213,China)
出处
《粉末冶金材料科学与工程》
2022年第4期389-397,共9页
Materials Science and Engineering of Powder Metallurgy
基金
国家自然科学基金资助项目(52072410)。
