Commercial-purity (99 wt pct), bulk, ultrafine-grained aluminum samples were produced by a two-step process that combines powder consolidation by hot isostatic pressing and dynamic plastic deformation. The compaction step yielded crystallographic texture-free specimens with an average grain size of approximately 2 μm. Then, some of the consolidated specimens were deformed dynamically at room temperature at an initial strain rate of 370 seconds -1 and up to an axial strain of ε = 1.25. After dynamic plastic deformation, the grain size and the dislocation density were approximately 500 nm and 10 14 m -2 , respectively. The yield strength was approximately 77 MPa for the as-consolidated sample, which increased up to approximately 103 MPa and 120 MPa for the impacted samples along the axial and radial directions, respectively. The compression stress as a function of strain showed saturation behavior for the axially deformed samples, whereas the specimens deformed along the radial direction exhibited significant strain softening. The latter behavior is explained mainly by the weakening of the crystallographic texture that occurred because of the strain-path change along the radial direction.
|Number of pages||11|
|Journal||Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science|
|Publication status||Published - Apr 2012|
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys