Plastic deformation of austenitic iron at intermediate strain rates

The plastic deformation of austenitic iron, represented by a zone-refined iron, an electrolytic iron, an Fe-0.05C alloy, and an Fe-5.2 Mn alloy, has been documented for the temperature range 950 to 1350°C (1740 to 2460°F) and the strain-rate range 2.8 x 10^-5 to 2.3 x 10^-2 s^-1. The intrusion of recrystallization during deformation restricts the documentation to initial periods of strain usually less than 0.10. The general problem of retaining grain structures representative of polycrystals in specimens annealed at temperatures above 0.95T _mis recognized, and a basis for its solution is presented. Chemical composion appears to influence the plastic-flow behavior of austenitic iron primarily through its effect on the grain structure. Thus, the large-grained zone-refined iron is relatively weak, and the difference in behavior between the Fe-0.05 C alloy and the Fe-5.2 Mn alloy is small. M. F. HOLMES, formerly Associate Scientist, U.S. Steel Corporation.