Abstract

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.

摘要

2205双相不锈钢（DSS）是一种结构复杂的不锈钢，兼有奥氏体和铁素体不锈钢的优点。与300系列不锈钢相比，具有更好的性能，可以在更恶劣的环境下使用。通过铝热反应制备了具有异质复合结构的块体2205 DSS。铁素体相体积百分比为32.3%，奥氏体相体积百分比为59.7%，σ相为8.1%。纳米晶和超细奥氏体的平均晶粒尺寸为20.9 nm，占74.2%。相对力学性能变差，属于脆性断裂。通过断口观察分析了双相结构和微/纳米结构的共同作用机制。现在，铸态异质复合结构2205 DSS的抗拉强度和断裂伸长率较差。因此，需要采用不同的轧制和退火系统，通过组织设计来粗化晶粒和调整力学性能。