界面反应对SiC/Ti基复合材料界面结合强度的影响机理

项目名称： 界面反应对SiC/Ti基复合材料界面结合强度的影响机理

项目编号： No.50871086

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 轻工业、手工业

项目作者： 杨延清

作者单位： 西北工业大学

项目金额： 37万元

中文摘要： 揭示了SiC/Ti6Al4V、SiC/Ti-43Al-9V等复合材料的界面反应和元素扩散的规律和机理，揭示了界面反应对基体微观组织的影响规律，扫描电镜原位观察揭示了拉伸过程中裂纹扩展规律，发现SiC纤维的C涂层可以有效地偏转裂纹，保护SiC纤维。采用有限元计算和多种实验测试（XRD、激光拉曼光谱、基片弯曲、去除基体等）的方法研究了SiC/Ti-6Al-4V复合材料残余热应力及其分布，重点考察了界面反应对残余热应力的影响规律以及各种涂层体系的作用，证明C涂层在提高复合材料横向以及轴向性能方面有较大的优势，确定了残余热应力的起始温度为700℃#12290;采用纤维顶出法测试和有限元计算研究了SiC/Ti基复合材料地界面结合强度，建立了界面反应层厚度和界面剪切强度之间的关系式。分析了纤维轴向应力分布,考虑了热残余应变能、试样制备过程中释放的应变能、泊松比、以及界面摩擦应力所消耗的应变能的影响，推导出了SiC/Ti基复合材料界面断裂韧性的计算公式。当不考虑上述影响因素时，即为国际上已有的计算公式,即，所推到的公式涵盖了国际上已有的公式。另外，计算结果表明本项目推导的公式更加精确。

中文关键词： SiC纤维；Ti基复合材料；界面反应；残余热应力;界面结合强度

英文摘要： The interfacial reaction and related element diffusion of SiC/Ti-6Al-4V and SiC/Ti-43Al-9V composites were investigated and its mechanism was revealed. the crack propergation during tensile was observed in situ by a SEM and it was found that the C-coating of SiC fiber plays an important role for deflecting the crack and protecting the fiber. The finite element calculation and various test methods, including XRD, Raman spectrometry, substrate bending and matrix eroding, were used to study the thermal residual stresses of the SiC/Ti composites. The effect of interfacial reaction layers and different coatings on the thermal residual stresses were emphasized in the study. It is confirmed that C-coating can increase the longidudinal and transverse mechanical properties and the starting temperture of the residual stresses was determented to be 700℃ The interfacial bonding strength of the SiC/Ti-matrix composites was studied by means of fiber push-out test and finite element calculation. A model of the interfacial shear strength related to the interfacial reaction was established based on the shear-lag theory. At last, a theoretical formula on the interfacial fraction toughness was deduced based on analyzing the stress distribution and considering the effects of the thermal residual strain, the released strain energy during sample preparation, the poisson's ratio and the strain energy exhausted by the interfacial friction. If such factors are omitted, the present formula is the same as those suggested by Kalton and by Majumdar. It means that their formulae can be included in the present formula. Furthermore, it is pointed out that more precise results be obtained by the present formula.

英文关键词： SiC fiber; Ti-matrix composites; interfacial reaction; thermal residual stress; interfacial bonding strength