Investigation on property and figuration for two kinds of needling fiber

The property of pre-oxidation fiber and carbon fiber which are suitable for fabricating the carbon fiber preform in needling process was studied,and the property of felt preparation and needling was compared.After carbonization,the tensile strength of pre-oxidation fiber is only 2 000 MPa,which is lower than the carbon fiber(≥3 000 MPa).The elongation-to-break of pre-oxidation fiber is 4 times as high as that of carbon fiber,the needling fiber is 3～4 times as long as the carbon fiber,and the length of the needling pre-oxidation fiber is 8～15 mm.The peel strength of 3K carbon clothes/pre-oxidation fiber felt perform reaches 0.594 MPa,and that of 3K carbon clothes/carbon fiber felt perform is 0.128 MPa.With high deformation resistance and structural integrity,the carbon fiber needling preform is suitable for making the high strength thin structure,such as the divergent cone and the extendible cone of the rocket motor.For the thick C/C(C/SiC) composites structure,such as throat and divergent cone of tactical missiles,the pre-oxidation fiber is superior.