Abstract: In this study effect of alpha prime (a) precipitate on the mechanical properties of thermally embrittled DSS has been investigated. Initially as received material was solutionized at 1070 C followed by water quenching in order to dissolve if any harmful precipitates were present. Then the samples were thermally embrittled by heating the samples at 475 C and water quenched for varying periods from 25 to 750 hours. Tensile and impact toughness tests were performed in order to evaluate the mechanical properties. Microstructure and fractured samples were examined by scanning electron microscope. Results showed that mechanical properties were significantly degraded when subjected to thermal ageing at 475 C which is one of the key limiting factor for the usage of Duplex stainless steels in power plants for long term applications. Mechanism behind475 embrittlement was also investigated in this study.

Keywords: Duplex stainless steel; ageing; embrittlement; tensile strength; ductility; impact toughness.