The main goal is to solve the pore defect of the pultruded carbon fiber/phenolic resin Z-pin and obtain the three-dimensional reinforcement of ablation resistant composite. On basis of the analysis of the pore formation and phenolic resin curing process

the twisted yarn was utilized to elevate the resin's inner pressure to eliminate the pore defects in Z-pin. The results showed that

along with the increase of the twist number within the specific range

the size and amount of pores declined obviously

and also the phenolic resin mass fraction and maximum insertion depth decreased

while the compressive property arose firstly and declined afterwards. When the twist number was 80twist/m

Z-pin of good quality was obtained with approximately 32% phenolic resin mass fraction

which can be used for ultrasonic insertion

with the maximum insertion depth up to 10mm in room temperature.