The Evolution of Interfacial Microstructure and Fracture Behavior of Short Carbon Fiber Reinforced 2024 Al Composites at High Temperature

• Main Authors: Chi Zhang, Jinhao Wu, Qingnan Meng, Youhong Sun, Mao Wen
• Format: Article
• Language: English
• Published: MDPI AG 2019-08-01
• Series: Applied Sciences
• Subjects: carbon fiber; aluminum matrix composites; interfacial microstructure; mechanical properties; fracture behavior
• Online Access: https://www.mdpi.com/2076-3417/9/17/3477

The short carbon fiber reinforced 2024 Al composites were fabricated through powder metallurgy. The effect of short carbon fiber content on the interfacial microstructure and fracture behavior of the composites at different temperatures were investigated. The results showed that the dislocation accumulation was formed in the aluminum matrix due to the thermal expansion mismatch between carbon fiber and aluminum matrix. With the testing temperature increasing, the size of interfacial product Al₄C₃ and precipitates Al₂Cu became larger, and the segregation of Al₂Cu was found coarsening around Al₄C₃. The addition of short carbon fiber improved the hardness and modulus of the aluminum matrix in the vicinity of the interface between carbon fiber and aluminum matrix. Compared to the matrix 2024 Al, the yield strength and ultimate tensile strength of the composites first increased and then decreased with increasing short carbon fiber content at room temperature 423 Kand 523 K. The fracture surface of the composites at room temperature was characterized by shear failure of fiber, while the interface debonding and fiber pulled-out became predominant fracture morphologies for the fracture surface at increased temperatures.