正交铺层PIP-SiC_(f)/SiC复合材料的水淬失效行为EI北大核心CSCD

铺层方式是影响预浸料铺贴工艺制备SiC_(f)/SiC复合材料抗热震性能的关键因素之一。以先驱体浸渍裂解(PIP)工艺制备的SiC_(f)/SiC复合材料为研究对象,基于内聚力模型,对不同正交铺层方式的方形试样开展1200℃高温水淬实验及有限元仿真研究。结果表明:水淬过程中试样表面温度急剧下降,芯部与表面存在较大温差,顶角与芯部温差最高可达1077℃,导致复合材料的主要失效模式为层间开裂和基体开裂,且试样层间开裂位置与铺层方式有关。由模拟结果可知,由于正交铺层方式的不同,试样的层间开裂位移也存在显著差异:0/90]与0/90/0]两种铺层方式层间主裂纹开裂位移约为0.61 mm,而0/0/90/90]铺层主开裂位移仅为0.04 mm。此外,随着水淬时间的增加,层间主裂纹开裂位移逐渐增大,而次裂纹在开裂后逐渐发生闭合现象。

Water quenching failure behavior of orthogonal laminated PIP-SiCf/SiC composites

Laminating method is one of the key factors affecting the thermal shock resistance of SiC_f/SiC composites prepared by prepreg paving process. Based on the cohesion model, 1200 ℃ high temperature water quenching tests and finite element simulation studies were carried out on SiC_f/SiC composite square samples with different orthogonal lay-up methods, which were prepared by the precursor immersion pyrolysis(PIP) process. The results show that the surface temperature of the sample drops sharply during the water quenching process, and there is a large temperature difference between the core and the surface. The temperature difference between the corner and the core can reach up to 1077 ℃. The main failure modes are interlaminar delamination and matrix cracking, and the delamination position is related to the layering method. Moreover, significant differences in the delamination displacement can be observed, due to the difference in the orthogonal lay-up mode: tacking displacement of the main interlaminar delamination of 0/90] and 0/90/0] can reach 0.61 mm, while the 0/0/90/90] layer cracking displacement is only 0.04 mm. In addition, the cracking displacement of the main interlaminar delamination increases gradually with the increase of water quenching time, while the secondary cracks will undergo crack closure after opening.