CHARPY-V TRANSITION TEMPERATURES OF FERRITIC IRON ALLOYS. PART I. IRON- OXYGEN AND IRON-ALUMINUM

Technical Report · Sat Jan 31 23:00:00 EST 1959

OSTI ID:4263344

Srawley, J E

The mid-energy Charpy-V transition temperatures of a series of Fe-O alloys and a series of Fe-Al alloys were determined for several conditions of mechanical working and heat treatment. The 50% ductile fractureappearance transition temperatures were the same as the mid-energy temperatures for all practical purposes. The transition temperature of Fe increased steadily with the O content for any given condition among those studied. For a given O content the transition temperature was higher if the material had been furnace cooled from 1650 deg F after being cold worked than if it had been oil quenched from 1650 deg F after cold working. The mode of fracture below the transition temperature was intergranular for annealed irons containing 0.0039% O or more, and transgranular for quenched irons containing 0.0206% O or less. This confirms the finding of Rees and Hopkins that O causes intergranular embrittlement of Fe and suggests further that, by solution treatment and quenching, the embrittling agent can be dispersed from the grain boundaries to an extent depending upon the O content. In Fe-Al alloys the mode of fracture below the transition temperature was invariably transgranular. The transition temperatures decreased somewhat as the Al content increased from 0.2% to 2.0% and then increased rapidly as the Al content increased further. In contrast with the Fe--O series, the transition temperatures and hardnesses were higher in the quenched condition than in the annealed condition. A basis for an explanation of this is the assumption that 0 may have sufficient solubility in Fe-Al solid solutions to have a precipitation hardening effect, occurring during quenching. (auth)

• Research Organization: Naval Research Lab., Washington, D.C.
• NSA Number: NSA-13-011866
• OSTI ID: 4263344
• Report Number(s): NRL-5290; NR-510-000
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALUMINUM ALLOYS-- ANNEALING-- CHARPY TEST-- HARDNESS-- HEAT TREATMENTS-- IMPACT SHOCK-- IRON ALLOYS-- MATERIALS TESTING-- MECHANICAL PROPERTIES-- OXYGEN-- PRECIPITATION-- SOLID SOLUTIONS-- SOLUBILITY-- TEMPERATURE-- TRANSITION TEMPERATURE
BRITTLENESS-- CHARPY TEST-- COLD WORKING-- COOLING-- FAILURES-- FURNACES-- GRAIN BOUNDARIES-- HEAT TREATMENTS-- IMPACT SHOCK-- IRON OXIDES-- MATERIALS TESTING-- MECHANICAL PROPERTIES-- MELTING POINTS-- TEMPERATURE- - TRANSITION TEMPERATURE
METALLURGY AND CERAMICS