Hygrothermal mechanical properties of domestic carbon fiber/bismaleimide resin composites for aviation application

Abstract

The composites were separately prepared by a domestic T700-grade carbon fiber used for aviation and four types of bismaleimide resin. The composite laminates were treated by three hygrothermal conditions, including 100 ℃ boiling water, 70 ℃ water immersion and 70 ℃/85% relative humidity to study the hygrothermal mechanical properties of the composite laminates related to interface and matrix under ambient temperature and 150 ℃. The results show that the moisture absorption decreases the mechanical properties of composites, and the effect on mechanical properties under high temperature is significant. Furthermore, 90o tensile property, 0o compressive strength, flexural strength and open-hole compressive strength are sensitive to moisture absorption and temperature, while the sensitivities of 0o compressive modulus, flexural modulus and open-hole tensile strength are small. By comparing the changes of the mechanical properties of composite after different hygrothermal treatment conditions, it is found that the degree of degradation after 100 ℃ boiling water is larger, which is believed to be related to its higher equilibrium moisture absorption rate. Based on fracture morphology of composite after 90o tensile testing using scanning electron microscope, it is considered that the hygrothermal property of interface is the critical factor to determine the hygrothermal property of domestic carbon fiber composite.

Keywords

• carbon fiber composite
• bismaleimide resin
• hydrothermal treatment
• mechanical property
• interface