Influence of Extrusion Ratio on Microstructures and Properties of Cu-17Ni-3Al-X Alloy

The microstructures and mechanical properties of the Cu-17Ni-3Al-X alloy hot-extruded at different extrusion ratios were investigated by tensile and hardness testing, optical microscope (OM) and scanning electronic microscope.The results show that the dynamic re-crystallization occurs when the extrusion ratio λ increases from 8 to 25. The grain size and the second phases of the extruded alloys are obviously finer than that of the as-cast alloy. The mechanical properties of the extruded alloys are improved remarkably. The alloy with the λ of 25 obtained the tensile strength of 1025MPa, Brinell Hardness of 312HB and elongation of 10.0% which is 35%, 14% and 355%, respectively, higher than that of the as-cast alloy.