Phase Characterization and Formation Behavior in 6 wt％ Si High-silicon Austenitic Stainless Steel during Isothermal Aging

• 作者: Sihan Chen Tian Liang Yangtao Zhou Weiwei Xing Chengwu Zheng Yingche Ma JinMing Wu Guobin Li Kui Liu
• 来源期刊: 金属学报（英文版）
• 年，卷（期）: 2021,（5）
• 页码范围: 649-656
• 页数: 8页
• 语种: 英文

摘要

The precipitation behavior of different phases in a high-silicon stainless steel(6 wt％Si)during aging at 600-1050℃for 24 h was investigated.The morphology,crystal structure and composition of various precipitates were detailly characterized using optical microscopy,scanning electron microscopy and transmission electron microscopy.Four phases were mainly identified:x-phase,M6C carbides,σ phase and a new type of fcc-phase.During aging at 600-900℃,the main precipitate was(Cr,Mo and Si)-rich x-phase which was directly precipitated from γ matrix.The x-phase was calibrated as bcc structure with a lattice parameter of 8.90 ?.The peak temperature for the precipitation of x-phase was 800℃,and it was dissolved when aging at temperatures above 1000℃.The σ-phase was observed only at 700℃and grew next to x-phase.Above 700℃,a new fcc-phase was found to be precipitated along with x-phase,with a space group of Fd3c and a lattice parameter of 12.56 ?.The M6C carbides started to be precipitated at 700℃ in the vicinity of x-phase.And its amount basically increased with the increasing of temperature.An orientation relationship between M6C/γ was found:[100]c//[100]y,(001)c//(001)γ,i.e.,the cube-on-cube relationship.