Fracture of Nanocrystalline Aluminum

Bulk nanocrystalline (NC) alloys are an exciting new class of materials that have only recently established their potential for real-world applications. The tensile yield strength of nanocrystalline 5083 aluminum produced by consolidation of cyromilled powders is about twice that of conventional 5083 as shown in Fig. 1. The material is extruded which accounts for the anisotropy in tensile properties and has a grain size on the order of 50 nm. The elongation to failure is lower than for conventional coarse-grained 5083, however not much different from similar high strength alloys such as 5082-H19: 370 MPa yield strength, 4% elongation [

1

]. In addition, these materials are thermally stable; heating tensile bars to 500C for 2 hours results in only modest loss in room temperature strength.