文章信息/Info

Title:

 Effect of preform on thermal expansion coefficient of C/C composites

作者:

 曹偉鋒; 李賀軍; 郭領(lǐng)軍; 李偉; 鄧海亮

 （西北工業(yè)大學(xué) 凝固技術(shù)國家重點實驗室，C/C復(fù)合材料工程技術(shù)中心, 陜西 西安 710072）

Author(s):

 CAO Weifeng;  LI Hejun;  GUO Lingjun;  LI Wei;  DENG Hailiang

 (Northwestern Polytechnical University, solidification technology State Key Laboratory, C/C composite material research center, Xi’an, 710072)

關(guān)鍵詞:

 ; C/C復(fù)合材料; 預(yù)制體; 熱膨脹系數(shù)(CTE)

分類號:

TB 332

DOI:

10.7502/j.issn.1674-3962.2013.11.06

文獻標(biāo)志碼:

A

摘要:

 以天然氣為前驅(qū)氣體，整體碳氈和2D針刺碳氈為預(yù)制體，采用熱梯度化學(xué)氣相滲積技術(shù)制備了兩種C/C復(fù)合材料，其表觀密度均為1.74 g/cm³。借助光學(xué)顯微鏡和掃描電子顯微鏡觀察了熱解炭基體的生長特征和微觀形貌，采用熱膨脹儀測量了兩種材料的熱膨脹系數(shù)（CTE）, 研究了由不同預(yù)制體增強C/C復(fù)合材料的CTE，解釋了造成材料不同方向CTE差異的主要原因。結(jié)果表明，隨著溫度升高，材料A和B的CTE是逐漸升高的，且Z向CTE值均大于XY向。當(dāng)兩種材料在Z向的纖維體積分?jǐn)?shù)接近時，隨著XY方向纖維體積分?jǐn)?shù)增大，材料在Z向的CTE增大，在XY向的CTE降低，兩種材料在XY和Z向的CTE呈如下分布：α_B-Z>α_A-Z>α_A-XY>α_B-XY。C/C復(fù)合材料的CTE主要取決于纖維體積分?jǐn)?shù)和排布、炭基體及材料中的孔隙分布情況，前者起決定作用。

Abstract:

 Using natural gas as precursor gas, intergrated carbon felt and 2D needle carbon felt as preforms, two kinds of C/C composites were prepared by thermal gradient chemical vapor infiltration, and both of them have a same density of 1.74 g/cm³. With help of optical microscope and scanning electronic microscope, the growth characteristic and microstructure of pyrolytic carbon matrix were observed, and thermal expansion testing machine was employed to measure their thermal expansion coefficient (CTE). The CTE of C/C composites reinforced by different preforms was studied, and the CTE difference in different direction was explained. The results shows that, the CTEs of composite A and B gradually increases with increasing temperature, and the CTE in Z direction is higher than that in XY direction. When the fiber volume fraction of two composites in Z direction is near, with the fiber volume fraction in XY direction increasing, their CTE increase in Z direction and decrease in XY direction displaying α_B-Z>α_A-Z>α_A-XY>α_B-XY. The CTE of C/C composites mainly depends on the volume fraction and arrangement of carbon fiber in preform, carbon matrix and porous distribution, and the former has decision action.