Effect of Heterogeneous Composite Structure on the Microstructure and Properties for Nanostructured 2205 Duplex Stainless Steel

• Published in: Integrated ferroelectrics 2021-06, Vol.217 (1), p.190-197
• Main Authors: Ma, Guocai, Sheng, Jie, Meng, Qian, Du, Mingchen, La, Peiqing, Zheng, Yuehong, Wei, Ying, Zhan, Faqi, Wu, Dan
• Format: Article
• Language: English
• Subjects: Aluminothermic reactions; Austenite; Austenitic stainless steels; combinative action mechanisms; Composite structures; Dual phase steels; Duplex stainless steel; Duplex stainless steels; Elongated structure; Ferrite; Ferritic stainless steel; Ferritic stainless steels; fracture morphology; Grain size; heterogeneous composite structure; Mechanical properties; mechanical property; Sigma phase; Solid phases; Tensile strength; Ultrafines
• ISSN: 1058-4587; 1607-8489
• DOI: 10.1080/10584587.2021.1911311

2205 duplex stainless steel (DSS) is a kind of complex structure stainless steel, which has advantages of both austenitic and ferritic stainless steel. Compared with 300 series stainless steel, it has better performance and can be used in more severe environment. Bulk 2205 DSS with heterogeneous composite structure is prepared via aluminothermic reaction. The volume percentage of ferrite phase is 32.3%, that of austenite phase is 59.7%, and σ phase is 8.1%. Average grain size of nanocrystalline and ultrafine austenite is 20.9 nm, accounting for 74.2%. The relatively mechanical properties deteriorate, which belongs to brittle fracture. The joint action mechanism of dual-phase structure and micro/nanostructure is analyzed by fracture observation. At present, the tensile strength and fracture elongation of as-cast heterogeneous composite structure 2205 DSS are poor. Therefore, different rolling and annealing systems are needed to coarsen grains and adjust mechanical properties through structure design.