Microstructure and mechanical properties of z-pinned carbon fiber reinforced aluminum alloy composites

Highlights: • Steel z-pinned carbon fiber/Al composites are fabricated by pressure infiltration. • The interlaminar shear strength of the composites is increased by 70%–230%. • An interfacial reaction layer of FeAl3 is identified and characterized. - Abstract: We report that metal z-pin can be used to enhance the interlaminar strength of carbon fiber reinforced aluminum alloy (Cf/Al) composites. The Cf/Al composites incorporated with AISI 321 steel z-pins as interlaminar reinforcement were fabricated by pressure infiltration, resulting in high composite density. The steel pin reacted with the Al alloy matrix and formed a continuous interfacial reaction layer of FeAl₃ to provide strong interfacial bonding between the steel pin and Al alloy matrix. Moreover, it has been found that the diameter of the z-pin has a significant influence on the thickness of the interfacial reaction layer. Double-notched interlaminar shear testing showed that the z-pins increased the shear strength of the Cf/Al composite by 70%–230%.