摘要
后高温热处理对反应熔融浸渗法(RMI)制备C/C-SiC复合材料的微观结构与性能有着至关重要的影响。为研究后高温热处理对RMI制备C/C-SiC复合材料微观结构和力学性能影响及机制,本文通过等温化学气相渗透法(CVI)工艺,以天然气为碳源气体,氮气为载气和稀释气体,在碳纤维预制体内部沉积热解碳基体,制得密度为1.2 g/cm^(3)的C/C多孔体,然后通过RMI制备出C/C-SiC复合材料,研究了不同后高温热处理温度对C/C-SiC复合材料相组成、内应力及力学性能的影响。将制备得到的C/C-SiC复合材料分别在1300℃、1500℃和1700℃下进行后高温热处理,研究了后高温热处理对C/C-SiC复合材料密度、孔隙率、基体成分、内应力及对弯曲性能的影响。结果表明:经1300℃、1500℃及1700℃后热处理后,C/C-SiC复合材料的密度降低,开孔率增加,SiC基体含量上升,SiC基体的分布更为广泛,同时还伴随有残余Si挥发产生的大孔,残余Si含量显著降低。在1300℃、1500℃和1700℃的后热处理导致弯曲强度先增加后减小,1500℃后处理时弯曲强度最大为296.52 MPa,随着后处理温度提高,弯曲模量降低,1700℃后热处理下降程度最大。
The microstructure and properties of C/C-SiC composites prepared by reactive melt infiltration(RMI)are significantly affected by post-heat treatment.In order to study the effect and mechanism of post-heat treatment on the microstructure and mechanical properties of C/C-SiC composites prepared by RMI,the isothermal chemical vapor infiltration(CVI)process was used to deposit pyrolytic carbon matrix in the carbon fiber preform,and C/C porous bodies with a density of 1.2 g/cm^(3) were prepared by using natural gas as carbon source gas and nitrogen as carrier gas and dilution gas.Then C/C-SiC composites were prepared by reactive melt infiltration method.The effects of different post-heat treatment temperatures on the phase composition,internal stress and mechanical properties of C/C-SiC composites were studied.The prepared C/C-SiC composites were treated at 1300℃,1500℃and 1700℃,respectively.The effects of post-high temperature heat treatment on the density,porosity,matrix composition,internal stress and bending properties of the C/C-SiC composites were investigated.The results show that after heat treatment at 1300℃,1500℃and 1700℃,the density of C/C-SiC composites decreases,the porosity increases,the content of SiC matrix increases,the distribution of SiC matrix becomes more extensive,and the residual Si content decreases significantly with large pores caused by residual Si volatilization.At 1300℃,1500℃and 1700℃,the bending strength increases first and then decreases.At 1500℃,the bending strength reaches a maximum of 296.52 MPa.With the increase of the post-treatment temperature,the bending modulus decreases,and at 1700℃,the bending strength decreases the most.
作者
马飞
罗浩
孙守业
史祥东
罗瑞盈
郭灵燕
MA Fei;LUO Hao;SUN Shouye;SHI Xiangdong;LUO Ruiying;GUO Lingyan(State Key Laboratory of Engine Reliability,Weichai Power CO.,LTD.,Weifang 261000,China;Research Institute for Frontier Science,Beihang University,Beijing 100191,China)
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2024年第8期4375-4385,共11页
Acta Materiae Compositae Sinica
基金
内燃机与动力系统全国重点实验室开放课题(WCDL-GH-2020-0242)。
关键词
C/C-SIC
RMI
高温热处理
力学性能
微观结构
C/C-SiC
RMI
high-temperature thermal treatment
flexural properties
microscopic structure
