CREEP BEHAVIOR OF CARBON FIBER COMPOSITES

1994 Fiscal Year Final Research Report Summary

• Project/Area Number: 04452275
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: 金属材料(含表面処理・腐食防食)
• Research Institution: TOHOKU UNIVERSITY
• Principal Investigator: OIKAWA Hiroshi TOHOKU UNIV.FAC.OF ENG., PROFESSOR, 工学部, 教授 (30005243)
• Co-Investigator(Kenkyū-buntansha): SATO Hiroyuki TOHOKU UNIV.FAC.OF ENG., INSTRUCTOR, 工学部, 助手 (10225998)
• Project Period (FY): 1992 – 1994
• Keywords: C / C COMPOSITE / FOUR POINT BENDING / CREEP STRENGTH / CREEP / PLASTIC FLOW / HIGH TEMPERATURE STRENGTH / LONG-TERM STRENGTH

Research Abstract

High temperature bending and high temperature creep tests of eight layr C/C composites have been investigated and following results have been obtained.
(i) C/C composites creep at 1573K.The creep behavior is classified into logarithmic creep.
(ii) Slope of displacement-log (time) diagram depends on the applied load and increases as increasing load.
(iii) No obvious temperature dependence of yield stress has been observed at 1373-1573K.
(iv) C/C composites fracture at lower loads than UTS of fibers.
(v) Flow of the matrix strongly affects the yield strength and creep strength of C/C composites.
These results strongly suggest that strengthening of the matrix is important to improve long-term high-temperature strength.
As conclusions, it is suggested that prediction of long-term deformation characteristics of C/C composite be not possible based on the short-term deformation characteristics. Information of long-term high-temperature deformation characteristics of C/C composites is still lacking and further experimental investigation concerns with effects of deformation conditions are required to improve long-term strength.