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Time-temperature-precipitation behavior in al-li alloy 2195
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Bhat, B. N. Chen, P. S. |
| Copyright Year | 2002 |
| Description | Transmission electron microscopy was used to study time-temperature-precipitation (TTP) behavior in aluminum-lithium (Al-Li) 2195 alloy. Al-Li 2195 (nominally Al + 4 percent Cu + 1 percent Li + 0.3 percent Ag + 0.3 percent Mg + 0.1 percent Zr) was initially solutionized for 1 hr at 950 F and then stretched 3 percent. Heat treatments were conducted for up to 100 hr at temperatures ranging from 200 to 1,000 F. TTP diagrams were determined for both matrix and subgrain boundaries. Depending upon heat treatment conditions, precipitate phases (such as GP zone, theta'', theta', theta, delta', T1, TB, and T2) were found in the alloy. The TTP diagrams were applied as a guide to avoid T1 precipitation at subgrain boundaries, as part of an effort to improve the alloy's cryogenic fracture toughness (CFT). New understanding of TTP behavior was instrumental in the development of a two-step artificial aging treatment that significantly enhanced CFT in Al-Li 2195. |
| File Size | 1701241 |
| Page Count | 21 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20020030744 |
| Archival Resource Key | ark:/13960/t6m092j0f |
| Language | English |
| Publisher Date | 2002-02-01 |
| Access Restriction | Open |
| Subject Keyword | Metals And Metallic Materials Heat Treatment Transmission Electron Microscopy Copper Alloys Aluminum-lithium Alloys Cryogenics Aging Metallurgy Fracture Strength Microstructure Precipitation Hardening Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
