时效工艺对2205双相不锈钢组织与力学性能的影响

Effects of ageing treatment on microstructure and mechanical behavior in duplex stainless steel 2205

研究了时效温度和时间对2205双相不锈钢组织及力学性能的影响,并对其断口形貌进行了分析。结果表明,2205不锈钢在时效处理中析出相σ相的形核位置、形态及数量与时效温度和时间有很大关系。时效温度高时,σ相在δ/γ相界和δ相内同时形核、生长,并且易形成块状;温度低时,σ相则偏聚在δ/γ相界生核,然后向δ相内生长,σ相易形成片状组织;同时,σ相的数量也会随着时效时间的延长而增加。475℃和600℃时效后双相不锈钢的强度明显提高,韧性略有降低,微观断口以韧窝为主。750℃时效后强度有所提高,韧性明显降低,微观断口以解理平面为主。

The influence of ageing treatment on microstructure and properties in duplex stainless steel 2205 was studied,and the corresponding fractography was analyzed.The results are as follow： The ageing temperature and time have great relations to the nucleant site,shape and the amount of the σ phase.When the aging temperature is high,σ-phase at δ / γ phase boundary and δ-phase will nucleate,grow,and easily form massive texture.When temperature is low,σ phase will form segregation at the δ / γ phase boundary for nucleation,then grow in the δ-phase,and σ-phase will easily form lamellar structures;meanwhile,as the ageing time is longer,the quantity of σ-phase will increase.Ageing at the temperature of 475℃and 600℃ makes remarkable rise of the strength,but less decrease of the plasticity.The dimples are found on the fracture surface of specimens.Aging at 750℃ makes rise of the strength,but leads the significant decrease of the impact properties,the facet exists on the fracture surface.