SiC/Ti基复合材料中纤维排布方式对残余热应力的影响

采用ANSYS有限元分析软件，对SCS－6 SiC／Ti－24A1－11Nb复合材料的残余热应力进行数值模拟，重点分析了纤维排布对残余热应力的影响。结果表明，在高温和热等静压成型的工艺条件下，与四方纤维排布模型相比，六方纤维排布模型的残余热应力较小，应力分布也较均匀，不易导致基体开裂。研究结果为SiC纤维增强Ti基复合材料的制备方法和工艺提供了一定的依据。

Finite Element Analysis of Residual Thermal Stress in SCS-6 SiC/Ti-24Al-11Nb Composite

Residual thermal stress which affects all round properties of composites greatly is inevitable due to the mismatch of the thermal expansion coefficients (TEC) between the fiber and matrix. It was analyzed by using finite element simulation in SCS-6 SiC/Ti-24Al-llNb composite. Three models of fiber array in the composite were considered and temperature-dependent material properties were used. Compression stress was found in the radial direction and tensile stress in the tangential direction in all the three models. However, in single fiber model, the residual stress is more homogenous and smaller compared to the square-fiber geometry and the hexagonal-fiber geometry. It is pointed out that, in real composite system, hexagonal-fiber geometry is superior because the distribution and the magnitude of the residual stress are similar to that in single fiber model. In square-fiber geometry, it is easer to make the matrix crack due to the larger residual tangential stress, especially at the position with smaller fiber distance.