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The strength and ductility of polycrystalline nial in tension
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Schulson, E. M. |
| Copyright Year | 1982 |
| Description | Experiments at temperatures from 20 C to 400 C at two strain rates (.0001/s and .000005/s) establish that: (1) at room temperatures, binary and microalloyed ( 1000 ppm La, Y, Mo, Ti) NiAl shows negligible ductility, independent of grain size over the range 5 to 140 micrometers; (2) at 295 C the tensile elongation of binary 51 Ni/49 Al increases from 1% to about 5% upon decreasing the grain size to below approximately 10 micrometers; (3) similarly, at 400 C the ductility increases from about 2% to 15% upon decreasing the grain size to below 15 micrometers; (4) the ductility of fine grained (7 micrometer) binary aggregates deformed at 295 C increases from approximately 5% to 12% upon decreasing the strain rate from .0001/s to .000005/s; (5) partial recrystallization (10% to 20%) of warm extruded binary and microalloyed material imparts 1% to 2% ductility at room temperature where fully recrystallized material is brittle; (6) the yield strength obeys a Hall-Petch relationship; and (7) when ductility is not observed, fracture coincides with yielding. The mechanisms underlying the flow and fracture of NiAl are discussed in terms of the nucleation and growth of microcracks. The concept of a critical grain size is considered in the light of the results. |
| File Size | 179477 |
| Page Count | 8 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19830003031 |
| Archival Resource Key | ark:/13960/t1ng9gc3c |
| Language | English |
| Publisher Date | 1982-10-01 |
| Access Restriction | Open |
| Subject Keyword | Metallic Materials Grain Boundaries Microcracks Fracture Mechanics Nucleation Ductility Alloys Intermetallics Polycrystals Aluminum Alloys Nitrogen Tensile Strength Binary Alloys Yield Strength Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
