STUDY OF MICROSTRUCTURAL EVOLUTIONS IN LEAN DUPLEX 2101 DURING AGING

摘要

The influence of isothermal aging on the microstructure of the lean duplex stainless steel 2101 with composition Fe-21.5Cr-5Mn-l.6Ni-0.22N-0.3Mo was investigated. The kinetics of precipitation and phase evolution were followed from few minutes to thousands of hours of aging particularly with thermoelectric power(TEP)measurements. Precipitation of Cr_2N nitrides after few minutes of aging at 690°C were indexed by EBSD and led to an increase of TEP coefficient. Similarly a-phase formation led to a big drop of TPE from 10 hours of aging at 690°C. These mechanisms deplete respectively ferrite then austenite in chromium which transform to martensite during water quenching.