Microstructures and Bending Property of Mesophase Based C/C Composites with Air Oxidation Process

Abstract

Carbon-carbon composites were fabricated in short period by LPIC(low pressure impregnation car-bonization) process with 225 ℃ air oxidation using mesophase pitch as precursor.The microstructures were ob-served by PLM(polarizing microscope).The bending property and fracture surface were tested by universal testing machine and SEM(scanning electron microscope),respectively.The results show that the carbon yield is improved remarkably with 225℃ air oxidation compared with the samples without air-oxidation.After four cycles of LPIC,the density of C/C composites reaches 1.73 g/cm3.Its bending property is 152.39MPa,which is increased 62.87% compared with the samples without air oxidation process.It is concluded that the C/C composites with air oxidation exhibit pseudo-plastic failure behavior and the samples without air-oxidation rupture from interlays with low bend-ing strength.The microstructures of C/C composites without air oxidation are mainly small domains with few mo-saic and domain textures.Nevertheless,the composites with 225℃ air oxidation present domain textures mainly with small domain and flow domain.