SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING Application of stainless steels, AISI 300 series, has been widely accepted in industry owing to their excellent combination of strength, ductility, toughness and corrosion resistance. However the alloying elements, nickel and chromium, contained in conventional stainless steels are strategically important and very expensive. In order to assure adequate supply of stainless steels in the future many studies have been done to explore the possibility of the substitution of manganese and aluminum for nickel and chromium. Though the FeMnAl system has attracted many intensive studies in recent years the data obtained are still far from complete. It is apparent that a lack of knowledge still exists concerning the mechanical behavior with respect to various hardening mechanisms including various aging temperatures and times, combination of strain hardening and aging, employment oI pre-aging in the thermomechanical processes and in particular the relationship between the microstructure and their resulting mechanical properties 热机的SCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING Application of stainless steels, AISI 300 series, has been widely accepted in industry owing to their excellent combination of strength, ductility, toughness and corrosion resistance. However the alloying elements, nickel and chromium, contained in conventional stainless steels are strategically important and very expensive. In order to assure adequate supply of stainless steels in the future many studies have been done to explore the possibility of the substitution of manganese and aluminum for nickel and chromium. Though the FeMnAl system has attracted many intensive studies in recent years; the data obtained are still far from complete. It is apparent that a lack of knowledge still exists concerning the mechanical behavior with respect to various hardening mechanisms including various aging temperatures and times, combination of strain hardening and aging, employment of pre-aging in the thermomechanical processes and in particular the relationship between the microstructure and their resulting mechanical properties. 热机的