The effect of strain rate on strain-induced -martensite transformation and mechanical behavior of austenitic stainless steel grades EN 1.4318 (AISI 301LN) and EN 1.4301 (AISI 304) was studied at strain rates ranging between 3 ϫ 10 Ϫ4 and 200 s Ϫ1 . The most important effect of the strain rate was found to be the adiabatic heating that suppresses the strain-induced transformation. A correlation between the work-hardening rate and the rate of transformation was found. Therefore, the changes in the extent of the ␣Ј-martensite formation strongly affected the work-hardening rate and the ultimate tensile strength of the materials. Changes in the martensite formation and workhardening rate affected also the ductility of the studied steels. Furthermore, it was shown that the square root of the ␣Ј-martensite fraction is a linear function of flow stress. This indicates that the formation of ␣Ј-martensite affects the stress by influencing the dislocation density of the austenite phase. Olson-Cohen analysis of the martensite measurement results did not indicate any effect of strain rate on shear band formation, which was contrary to the transmission electron microscopy (TEM) examinations. The ␤ parameter decreased with increasing strain rate, which indicates a decrease in the chemical driving force of the transformation. g S a¿ g S a¿ g S a¿ g S a¿ g S a¿

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The microstructures of a powder metallurgy/hot-isostatically pressed super duplex stainless steel, designed and manufactured for massive components of paper machines, were studied after heat treatments simulating the industrial production. It was shown that copper precipitates in the ferrite phase as phase. Morphologically, the copper precipitates are of two types-nearly spherical particles of typical size from 30 to 50 nm, and rodlike particles 30-to 35-nm wide, and up to 700-nm long. The main observations on copper precipitation in modern super duplex stainless steels are similar to those in low-alloy steels. Copper particles were shown to be the nucleation sites for the formation of secondary austenite and to pin the boundaries of sigma phase.

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