Effect of heat-treatment on the tensile behavior or iron-rich FeAl and FeAl + B
- Dartmouth College, Hanover, NH (United States). Thayer School of Engineering
Both test environment and heat-treatment have been demonstrated to have a substantial effect on the room-temperature mechanical properties of iron-rich B2-structured FeAl. Different heat-treatments also affect the ductility. Polycrystals of Fe-40Al show greater elongation when furnace-cooled than when oil-quenched or air-cooled. Similarly, after a low temperature anneal, Fe-45Al can exhibit [approximately]3% elongation when tested in air whereas without this anneal failure before yield occurs under tension. Polycrystals of boron-doped Fe-40Al show similar behavior. The fracture mode of the boron-doped material was noted to change from mixed mode to completely transgranular cleavage with increasing cooling rate, whereas higher cooling rates have been reported to increase the incidence of intergranular fracture for unalloyed FeAl. The cooling rate also dramatically affects the ductility of polycrystals in compression: for iron-rich alloys, the shortening to failure is reduced at higher cooling rates while for the stoichiometric composition a higher cooling rate can lead to fracture before yield. Interestingly, single crystals of Fe-40Al exhibit little difference in their fracture strains whether they are oil-quenched, air-cooled or furnace-cooled, although the ultimate tensile strength is less for the furnace-cooled crystals than those for the other heat-treatments. The present study was performed to examine further the effect of various heat-treatments on the strength and ductility of unalloyed and boron-doped FeAl.
- DOE Contract Number:
- FG02-87ER45311
- OSTI ID:
- 5263961
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Vol. 30:5; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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