EFFECTS OF HYDROGEN TREATMENT ON THE DUCTILITY OF MOLYBDENUM UNDER 760 AND 10 TO THE MINUS 10TH POWER TORR.
Rept. for Mar 65-Jun 66,
AEROSPACE CORP EL SEGUNDO CA LABS DIV
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Room-temperature tensile experiments on polycrystalline molybdenum indicate a grain size and heat treatment contribution to the difference in strain-to-fracture of specimens deformed at 760 Torr to those deformed at 10 to the -10th power Torr. The magnitude of the effect appears to depend critically on grain size and impurity distributions resulting from heat treatment with and without a hydrogen atmosphere. However, it has been determined that the ductility effects are predominantly due to a change in ductility of specimens tested at atmospheric pressure. Ultrahigh vacuum tensile behaviors are relatively unaffected. The largest difference in strain-to-fracture approximately 13 was in a narrow grain-size range in which specimens were first recrystallized and then soaked in a hydrogen atmosphere. The enhancement of ductility of hydrogen-treated specimens under vacuum suggests the involvement of a hydrogen-related gaseous contaminant. Author
- Metallurgy and Metallography