针刺预制体参数对C/C复合材料力学性能的影响

通过针刺与化学气相沉积分别制备碳纤维预制体与碳基体,获得针刺C/C复合材料.研究了针刺密度、针刺深度、网胎面密度等预制体成型工艺参数对C/C复合材料力学性能的影响,并探讨了预制体体积密度与C/C复合材料力学性能关联关系.结果表明,针刺密度在20～ 50针/cm2之间时,C/C复合材料拉伸强度先增后减,而层间剪切强度一直上升;针刺深度在10～16 mm之间时,拉伸强度和层间剪切强度随针刺深度的提高而增加;网胎面密度在100～300 g/m2之间时,拉伸强度和层间剪切强度随网胎面密度的提高而降低;当只改变针刺密度、针刺深度、网胎面密度其中一个成型参数时,拉伸强度和层间剪切强度受预制体密度影响显著,预制体密度可作为预测C/C复合材料力学性能的一个宏观成型参数.

Effect of needle-punched preform parameters on the mechanical properties of carbon/carbon composites

Carbon fiber preforms were prepared and then densified to produce carbon/carbon composites using needle-punching and chemical vapor infiltration technique,respectively.The effects of the preform manufacturing parameters,including the needlepunched density and its depth,and the mass-to-area (M/A) ratio of short-cut fiber felt,on the mechanical properties of the composites were investigated.The relation between the mechanical properties of the composites and the bulk density of the preforms was also discussed.Results show that the tensile strength of the composites increase and thereafter decrease as the needle-punched density increased from 20 to 50 pin/cm2,while the interlaminar shear strength of the composites tends to increase.The tensile and interlaminar shear strengths exhibit an increasing tendency with the increase of needle-punched depth from 10 to 16 mm,whereas they reduce as the M/A ratio of short-cut fiber felt is increased from 100 to 300 g/m2.Both the tensile and interlaminar shear strengths are dominated by the preform density when only one parameter of the needle-punched density and its depth,and the M/A ratio was varied.The preform density could be employed as a key macro-parameter to predict the mechanical properties of the composites.