时效处理对2205 DSS组织及力学性能的影响

首先对2205 DSS进行了1 100℃固溶处理,随后将试样分别在650,700,750,800,850和900℃下进行不同时间的时效处理,探究2205 DSS中σ相的析出规律及其对材料组织和力学性能的影响.研究结果表明:2205 DSS中σ相的析出分为有碳化物伴随和无碳化物伴随两种方式,前者发生在α-γ相界上,后者则主要发生在α相的晶内和晶界;2205 DSS在850℃时效时σ相的析出行为最严重;在析出σ相后,合金元素Cr和Mo在各相中会发生不同程度的偏聚;2205 DSS中析出少量的σ相对材料的塑性影响不大,但会显著降低材料的冲击韧性,而σ相的大量析出则会使两者均发生严重恶化;σ相的析出对材料的屈服强度影响不大,对材料的抗拉强度有略微的提高作用.

Influence of Ageing Treatment on Microstructures and Mechanical Properties of 2205 Duplex Stainless Steel

2205 DSS(duplex stainless steel)were solution treated at 1100℃ followed by aging at 650~900℃ for different time to study the precipitation of σ phase and its influence on microstructures and properties. The results showed that σ phase precipitates in two different ways， one is the precipitation at phase boundaries accompanied by carbides; the other is the precipitation in the ferrite grains or at the ferrite grain boundaries without accompanied carbides. The precipitation of σ phase is the most serious when aged at 850℃. After the precipitation， the segregation of alloying elements Cr and Mo in different phases occurs in different degrees. Small amounts of σ phase have little effect on ductility， but reduce impact toughness significantly. Large amounts of σ phase can reduce both ductility and impact toughness severely. The precipitation of σ phase has little effect on yield strength， and can improve tensile strength slightly.