Age-hardening susceptibility of high-Cr ODS ferritic steels and SUS430 ferritic steel

作者：Chen Dongsheng^*; Kimura Akihiko; Han Wentuo; Je Hwanil

来源：Fusion Engineering and Design, 2015, 98-99: 1945-1949.

DOI：10.1016/j.fusengdes.2015.05.078

• Phase decomposition
• Age-hardening
• Cr precipitates
• TEM
• ODS steel
• SUS430 steel

The effect of aging on high-Cr ferritic steels was investigated with focusing on the role of oxide particles in alpha/alpha' phase decomposition behavior. 12Cr-oxide dispersion strengthened (ODS) steel, 15Cr-ODS steel and commercial SUS430 steel were isothermally aged at 475 degrees C for up to 10,000 h. Thermal aging caused a larger hardening in SUS430 than 15Cr-ODS, while 12Cr-ODS showed almost no hardening. A characteristic of the ODS steels is that the hardening was not accompanied by the significant loss of ductility that was observed in SUS430 steel. After aging for 2000 h, SUS430 steel shows a larger ductile-brittle transition temperature (DBTF) shift than 15Cr-ODS steel, which suggests that the age-hardening susceptibility is lower in 15Cr-ODS steel than in conventional SUS430 steel. Thermal aging leaded to a large number of Cr-rich alpha' precipitates, which were confirmed by transmission electron microscopy (TEM). Correlation of age-hardening and phase decomposition was interpreted by Orowan type strengthening model. Results indicate that oxide particles cannot only suppress ductility loss, but also may influence a/a' phase decomposition kinetics.

• 出版日期2015-10