Superplasticity in Stainless Steels

摘要

Superplasticity involving unusually large elongations under low stresses can be obtained in polycrystalline materials. Large elongations can be obtained even in polycrystalline materials, which generally have poor ductility. If temperature and strain rate are chosen correctly, these materials can be deformed easily up to a large elongations (typically greater than 500 %) without necking. Microstructure of the materials to be superplastically deformed has some additional preconditions. Grain size of the materials has to be as small as possible and the presence of evenly distributed spheroidized secondary phase particles is also necessary. So far, the practical and commercial use of superplastic forming has been mainly applied for non-ferrous alloys such as titanium, aluminum and zinc alloys. The reason for the relatively minor use of superplastic forming of ferrous alloys has been explained to be due to the difficulty in making an additional commercial value with the use of superplasticity. Also, ferrous alloys have been claimed to have poor superplastic properties. This literature review on superplasticity in stainless steels.