The effects of environment on the room-temperature mechanical behavior of single-slip oriented FeAl single crystals

The effects of environment on fracture strain and yield strength have been studied in single-slip-oriented, iron-rich FeAl single crystals. During tensile tests, large fracture strains (>40%) ensue when tests are conducted in oxygen. In contrast, in air, elongations are <10%, whereas in vacuum typical elongations are ∼20–30%. Cathodic hydrogen charging has little effect on the ductility of crystals tested in air. Interestingly, intermittent straining in air produced more ductility than continuous straining. Tests performed in air on Fe–40Al showed lower yield strengths than tests performed in vacuum, and in interrupted tests in which straining was performed alternately in either air and vacuum, higher flow stresses were observed under vacuum than in air.