Microstructure, bending and shear properties of 2.5D shallow cross-linked C_f/Al composites

Abstract

2.5D shallow cross-linked Cf/Al composites with volume fraction of 50% were fabricated by vacuum pressure infiltration. The microstructure, bending and shear properties at room and high temperature were studied. The failure mechanism of bending and shear properties of the composites were analyzed. The results indicate that the warp and weft microstructures of 2.5D shallow cross-linked Cf/Al composites have some defects such as microvoid and fiber aggregation. The bending strength, bending modulus and shear strength of the composites at room temperature are 268.4 MPa,75.2 GPa and 41.0 MPa,respectively. The bending strength, bending modulus and shear strength of the composites at 350 ℃ are 139 MPa,70.9 GPa and 39.2 MPa,respectively. The bending strength,bending modulus and shear strength of the composites at 400 ℃ are 97.6 MPa,68.5 GPa and 29.9 MPa,respectively.The bending failure is mainly caused by the compressive stress on the inner surface, which leads to press fracture of the warp fiber bundle and the extrusion deformation of the weft fiber bundle. Tensile failure of composites is not obvious with the increase of testing temperature at the outer side tension. Shear failure occurs first in the damage interface of the matrix and fiber bundle, the fiber bundle is pulled out and the fracture surface is not at the same level at room temperature, the fracture of the fiber bundle shows 45° failure at 350,400 ℃.The buckling of the warp fiber bundle and the extrusion deformation degree of the weft fiber bundle become more and more serious with the increase of the test temperature.

Keywords

• 2.5d shallow cross-linked
• c_f/al composites
• microstructure
• bending property
• shear property