Weldability of polycrystalline aluminides
- Colorado School of Mines, Golden, CO (United States)
- Oak Ridge National Lab., TN (United States)
Iron aluminide alloy FA-129 is susceptible to cold cracking during gas-tungsten arc (GTA) welding. Cracking occurs by brittle fracture in the fusion zone, which has been attributed to excessive grain growth during solidification, in concert with environmental embrittlement. Previous work has shown that iron aluminide can be susceptible to environmental embrittlement when tested in the presence of water vapor. The suggested mechanism is similar to that observed in aluminum alloys: the reaction of water molecules with freshly exposed aluminum atoms at the crack tip results in the formation of high activity atomic hydrogen, which diffuses into the metal and causes embrittlement. This phenomenon occurs only when the metal is stressed, and therefore, is a dynamic embrittlement phenomenon. The same effect was not seen in experiments conducted in the presence of hydrogen gas. To further investigate this embrittlement problem and its effect on welding, GTA welds were conducted in atmospheres of varying amounts of water vapor on base material of varying grain sizes. The varying base material grain sizes were chosen because fusion zone grain size depends, to an extent, on the grain size of the base material. For example, a fine-grained base material should produce a finer grained fusion zone that a coarse-grained base material would. The results of the investigation are presented within this paper.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- OSTI ID:
- 140126
- Report Number(s):
- ORNL/FMP-93/1; CONF-9305135-; ON: DE94001091; TRN: 93:003927-0020
- Resource Relation:
- Conference: 7. annual conference on fossil energy materials, Oak Ridge, TN (United States), 11-13 May 1993; Other Information: PBD: Jul 1993; Related Information: Is Part Of Proceedings of the Seventh Annual Conference on Fossil Energy Materials; Fossil Energy AR and TD Materials Program; Cole, N.C.; Judkins, R.R. [comps.]; PB: 402 p.
- Country of Publication:
- United States
- Language:
- English
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