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Strength advantages of chemically polished boron fibers before and after reaction with aluminum
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Smith, R. J. Dicarlo, J. A. |
| Copyright Year | 1982 |
| Description | In order to determine their strength potential, the fracture properties of different types of commercial boron fibers were measured before and after application of secondary strengthening treatments. The principal treatments employed were a slight chemical polish, which removed low strength surface flaws, and a heat treatment in oxygen, which contracted the fibers and thereby compressed intrinsic bulk flaws. Those fiber types most significantly strengthened were 200 to 400 micrometers (8 to 16 mil) diameter boron on tungsten fibers produced in a single chemical vapor deposition reactor. The slight polish increased average tensile strenghts from 3.4 to 4.4 CN/m2 (500 to 640 ksi) and reduced coefficients of variation from about 15 to 3 percent. The oxygen heat treatment plus slight polish further improved average strengths to 5.5 GN/m2 (800 ksi) with coefficients near 3 percent. To ascertain whether these excellent properties could be retained after fabrication of B/Al composites, as produced and polished 203 micrometers (8 mil) fibers were thinly coated with aluminum, heat treated at B/Al fabrication temperatures, and then tested in tension and flexure at room temperature. The pre-polished fibers were observed to retain their superior strengths to higher temperatures than the as-produced fibers even though both were subjected to the same detrimental reaction with aluminum. |
| File Size | 2435529 |
| Page Count | 29 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19820013384 |
| Archival Resource Key | ark:/13960/t1tf4mv43 |
| Language | English |
| Publisher Date | 1982-01-01 |
| Access Restriction | Open |
| Subject Keyword | Composite Materials Boron Fibers Fractures Materials Heat Treatment Aluminum Boron Composites Fiber Strength Metal Polishing Tungsten Bending Boron Reinforced Materials Tensile 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 |
