Mechanism of improving strength and damping properties of powder-extruded Al/Zn composite after diffusion annealing
(1. Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China;
2. Key Laboratory for Advanced Materials Processing (Ministry of Education), University of Science and Technology Beijing, Beijing 100083, China)
2. Key Laboratory for Advanced Materials Processing (Ministry of Education), University of Science and Technology Beijing, Beijing 100083, China)
Abstract: In order to develop high strength, high damping and low density Al matrix composites, the Al/Zn composite bar samples with Zn mass fraction of 10%-40% were prepared by powder extrusion. The tensile strength and damping properties of the samples are improved by controlling both the Zn/Al diffusion degree and the precipitation of the interfacial phases. The results show that the tensile strength of the samples with Zn mass fraction of 10%-30% increases with the increases of both the Zn content and annealing temperature. When the Zn mass fraction increases to 40%, the tensile strength of the sample remains basically unchanged or decreases slightly, and the plasticity decreases gradually. Alloying of Al matrix and the formation of Zn/Al interface layer are mainly responsible for improving the strength of the annealed samples. The damping properties increase with the increases of both the Zn content and annealing temperature. The Zn/Al eutectoid lamella eliminates the detrimental effects on damping properties due to both alloying of the Al matrix and reduction of pure Zn in the Al matrix. The Al-30%Zn sample annealed at 350 °C for 0.5 h has good comprehensive properties, including the tensile strength of 330 MPa, the elongation to failure of 10% and the room-temperature damping properties (tan θ) of 0.025.
Key words: aluminum matrix composites; fiber reinforcement; mechanical properties; damping properties