Microstructure and properties of Al₃Zr/2024Al in situ composites after forging

To research the influencing rule of severe plastic deformation on Al matrix in situ composites, 10 wt% Al₃Zr/2024Al in situ particle-reinforced composite was prepared by direct melt reaction (DMR), and then, the composite was hot-forged by one direction with 90 % plastic deformation. Then, the microstructure of the forging state composite was observed, and the change law of mechanical properties and friction performances after and before plastic deforming was compared. The results indicate that the Al₃Zr-reinforced particle rotates and breaks into smaller size of 10–20 µm with the matrix flow; in addition, these smaller particles distribute more orderly in orientation and dispersedly. The 2024 matrix grain changes from as-cast tissue to fibrous tissue with length of 100 µm along the forging direction. Some mechanical properties of composites hot-forged by one direction with 90 % plastic deformation are improved much obviously. For example, the tensile strength is improved by 39.75 %, reaching 225 MPa, and the hardness is improved by 35.84 %, reaching HBW 76.83. Besides, the wear rate reduces, wear depth and area decline, and the wear-resisting property is improved after hot forging.