Abstract
Acoustic emission methods are used to investigate the evolution of internal microfractural damage during uniaxial compression of amorphous Zr-based foams with aligned, elongated pores. The foams are fabricated by means of densifying a blend of crystalline W powders and amorphous Zr-based powders with two oxygen contents (0.078 and 0.144 wt pct) by warm equal channel angular extrusion, followed by dissolution of the elongated W phase from the fully densified amorphous matrix. For the high-oxygen foams, prior powder boundaries in the amorphous struts promote damage that accumulates during compression, resulting in energy-absorbing properties comparable with the low-oxygen foams without stress-concentrating powder boundaries. The influence of pore orientation on the evolution of microfracture damage and the ability of the foams to accumulate damage without catastrophic failure is also investigated: pores oriented from 24 to 68 deg to the loading direction promote wall bending, resulting in foams with more diffuse damage and better energy-absorbing properties.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3114-3122 |
| Number of pages | 9 |
| Journal | Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science |
| Volume | 44 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 2013 |
Funding
MEC was supported by a National Science Foundation Graduate Research Fellowship. This research was partially funded by the Army Research Laboratory (ARL); the authors thank Dr. Suveen Mathaudhu (ARL, currently Army Research Office) for providing the L-26 samples and for helping to develop this project. The authors also thank Dr. Laszlo Kecskes (ARL) for many useful discussions, Mr. Micah Gallagher (ARL) for assistance in machining samples, Mr. Larry Jones (Ames National Laboratory, Department of Energy) for BMG powder and canning preparation; they acknowledge useful discussions with, and use of the ECAE equipment belonging to, Prof. K. Ted Hartwig (Texas A&M University, TAMU) as well as the experimental assistance of Mr. Robert Barber and Mr. David Foley (TAMU) in operating the equipment. The authors finally thank the Infrastructure Technology Institute at Northwestern University for providing access to their acoustic equipment.
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys