High Strength Bulk Nanostructured 2219 Al Alloy Produced by High Energy Ball Milling and Hot Pressing

The microstructure and mechanical properties of nano-crystalline 2219 Al alloy (Al-6.4Cu-0.29Mn, all in wt %) was studied. Nanocrystalline powders were produced from gas atomized 2219 Al alloy powders by high energy ball milling at room temperature. Powders were collected at different milling times and X-ray diffraction (XRD) analysis was used to evaluate grain size. High Vickers hardness (250HV), high compressive strength (920 MPa) and low ductility (2%) were observed in unimodal bulk nanostructured 2219 Al alloys consolidated to 99% density by hot pressing (HP). In addition, these nanocrystalline powders were blended with 15, 30 and 50% of (gas atomized) coarse-grained powders to obtain balanced mechanical properties of enhanced yield and ultimate strength and reasonable ductility and toughness as compared to either conventional or nanocrystalline 2219 alloys.