Microstructural characterization of delta/gamma/sigma/gamma(2)/chi phases in silver-doped 2205 duplex stainless steel under 800 degrees C aging

作者：Yang Sheng Min; Chen Yi Chun; Chen Chun Hung; Huang Wei Ping; Lin Dong Yih^*

来源：Journal of Alloys and Compounds, 2015, 633: 48-53.

DOI：10.1016/j.jallcom.2015.01.165

• Silver-doped 2205 duplex stainless steel
• Intermetallic compound
• sigma phase
• chi phase
• Phase transformations

In this study 0.2 wt.% Ag alloyed 2205 duplex stainless steels was selected as test material. The effect of aging time on the phase transformations of 0.2 wt.% Ag alloyed 2205 duplex stainless steel was investigated at 800 degrees C. Results show that the different intermetallic compounds (sigma and chi) were generated when the aging time increased at 800 degrees C. The Mo-enriched chi phase was firstly initiated at delta/gamma grain boundaries, but the Cr-enriched sigma phase was precipitated with the increase of aging time. Ag particles distributed over matrix stably and do not seem to influence microstructure evidently after aging treatment. From the quantitative analysis results, the sigma + chi phase volume fractions indeed would increase from 0.58% to 22.9% with the aging time in the period of 1-10 h at 800 degrees C. However, the sigma + chi phase tended to slow down while the aging time in the period of 10-100 h, and then the sigma + chi phase volume fractions rose from 22.9% to 31.33%. In addition, the delta phase volume fractions decreased and the gamma + gamma(2) phase volume fractions increased. Aging heat treatment at 800 degrees C changed the delta and gamma + gamma(2) phase volume fractions due to the delta -> chi + gamma(2) -> chi + sigma + gamma(2) phase transformations.

• 出版日期2015-6-5