| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Heterostructured and Gradient Materials (HGM VI): Principle, Processing and Properties
|
| Presentation Title |
Origins of High Strength and Dislocation Density in a Gradient Microstructure Revealed by a Simple Function |
| Author(s) |
Darcy Anne Hughes |
| On-Site Speaker (Planned) |
Darcy Anne Hughes |
| Abstract Scope |
Pressing and sliding nominally flat surfaces together creates gradients in structural size and strength with depth from the surface. Subsurface strengths reach 40% of theoretical maximum strength (E/10) via this method: micro ridges on a steel tool, high loads, and 77K in Cu plus 1-1.5% Fe from the steel. Samples at different temperatures and loads were statistically examined via microscopy. Deformation structures follow the principal of grain subdivision identified under different deformation modes. Measured structure/strength parameters include the spacing, D<sub>av</sub><sup>GNB</sup>, of deformation induced geometrically necessary boundaries that act like grain boundaries, and the incidental dislocation density in between, ρ<sub>av</sub><sup>ID</sup>. Universal scaling of deformation structures in fcc and bcc alloys, unified by stress and physical constants reveals mechanisms for enhanced dislocation density and strength at the nanoscale. Scaling persists across 2 to 4 orders of magnitude for stress: 30MPa-4.4GPa, strain, structural size: D<sub>av</sub><sup>GNB</sup>=10μm-2.8nm, and dislocation density: ρ<sub>av</sub><sup>ID</sup> =10><sup>13</sup>-10><sup>17</sup> m<sup>-2</sup>. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Iron and Steel, Copper / Nickel / Cobalt, Mechanical Properties |