Patent ID: 6994916

Claim:
A structural member, comprising: a first region comprising at least a portion of the exterior of the structural member, said first region being characterized by comparatively high operational stress; and a second region comprising at least a portion of the exterior of the structural member, said second region having a more refined grain structure than other portions of the structural member, said second region being formed by at least one of partial-penetration and full-penetration mixing and wherein said second region at least partially encompasses said first region to thereby selectively improve the strength, toughness and fatigue resistance of the structural member in said first region; and wherein the structural member defines a first set of regions having refined grain structures and a second set of regions having refined grain structures, said first set of regions being spaced apart and generally parallel, said second set of regions being spaced apart and generally parallel, and wherein said first set of regions intersects said second set of regions to thereby define a plurality of containment zones.