摘要
利用OM,SEM和TEM研究了一种超超临界用HR3C钢在700和750℃长期时效至2000 h过程中σ相的析出行为,借助相计算方法探究了影响σ相析出的因素.结果表明,HR3C钢在700和750℃时效1000 h就有不规则块状第二相在晶界析出,且随时效时间延长而增多和粗化;EDS分析表明该相主要含Fe和Cr,结合SAED的分析结果最终确定其为σ-FeCr金属间化合物;通过相计算方法对初始态HR3C钢进行分析认为,显微组织或相结构等差异可能是影响后续σ相析出行为的原因.
HR3C steel is a new type of austenitic heat-resistant steel which has been widely used for super- heater and re-heater tubes in the ultra-supercritical （USC） boiler. The mechanical properties of HR3C steel were de- pendent on the stability of the microstructure, particularly the large amount of precipitates formed during service. The precipitation of σ phase in HR3C steel during long-term aging for 2000 h at temperature of 700 and 750 ℃ was investigated by OM, SEM and TEM. The phase calculation method was applied to understand the factors in- fluencing the precipitation. After 1000 h of the aging duration, irregular mass second phase was found to pre- cipitate at the grain boundary, followed by the subsequent increasing and coarsening with time. The constituent ele- ments of the phases were determined as Fe and Cr through SEM equipped with EDS. Further SAED analysis re- suits led to the confirmation that these phases were basically σ-FeCr compound. Combined with the prediction made through New PHACOMP method, the microstructure or phase structure in initial state may affect the subse- quent precipitation behavior.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第8期920-924,共5页
Acta Metallurgica Sinica
基金
国家自然科学基金项目51171037和51134013资助~~
