Abstract
Dynamic torsional properties of ultra-fine-grained low-carbon steels fabricated by equal channel angular pressing (ECAP) was investigated. Dynamic torsional tests were conducted on four steel specimens, two of which were annealed after ECAP, using a torsional Kolsky bar. The ECAP'ed specimen consisted of very fine, equiaxed grains of 0.2 μm in size, which were slightly coarsened after annealing. The dynamic torsional test results indicated that maximum shear stress decreased with increasing annealing time, whereas fracture shear strain increased. Some adiabatic shear bands were observed at the gage center of the dynamically deformed torsional specimen. The adiabatic shear band formed in the 1-hr annealed specimen was about 10 μm wide, about twice as wide as the ECAP'ed specimen. However, the 24-hr annealed specimen showed nearly no void or adiabatic shear band formation, and thus fracture did not occur. Consequently, softening of the ECAP'ed specimen could be a good way to increase the fracture resistance under dynamic loading, as it reduced or prevented the formation of adiabatic shear bands or voids.
| Original language | English |
|---|---|
| Pages (from-to) | 135-140 |
| Number of pages | 6 |
| Journal | Materials Science and Technology |
| Volume | 1 |
| State | Published - 2004 |
| Event | Materials Science and Technology, MS and T 2004; Volume 1: AIST Process Metallurgy, Product Quality and Applications Proceedings - New Orleans, LA, United States Duration: 26 Sep 2004 → 29 Sep 2004 |
Keywords
- Adiabatic shear band
- Annealing
- Dynamic torsional test
- Equal channel angular pressing(ECAP)
- Ultra-fine-grained low-carbon steel