时效时间对2205双相不锈钢组织与疲劳裂纹扩展规律的影响  

Effect of aging time on microstructure and fatigue crack propagation behavior of 2205 duplex stainless steel

作　　者：黄澳 陈吉[1] 宋见[1] 刘元福[1] 常季 Huang Ao Chen Ji Song Jian Liu Yuanfu Chang Ji(School of Mechanical Engineering, Liaoning Shihua University, Fushun Liaoning 113001, China)

机构地区：[1]辽宁石油化工大学机械工程学院,辽宁抚顺113001

出　　处：《金属热处理》2016年第10期167-171,共5页Heat Treatment of Metals

基　　金：辽宁省自然科学基金(201202127)

摘　　要：对经1050℃固溶处理后的2205双相不锈钢进行850℃分别保温30、180、360 min时效处理,并采用光学显微镜、扫描电镜和力学性能测试等方法,研究了时效时间对2205双相不锈钢显微组织与疲劳裂纹扩展规律的影响。结果表明:经850℃时效处理后,沿α相内以及α相与γ相边界主要析出了σ相,并且,随着时效时间的延长,σ相的析出量增加,并逐渐形成片状组织。时效处理后试样的抗拉强度增大,塑性显著降低。随着时效时间的延长,试样的稳态裂纹扩展速率显著增大,疲劳裂纹扩展门槛值减小。等温时效处理后试样的断口形貌以解理断裂为主要特征,在σ相周围还出现有二次裂纹,这是由σ相的析出引起应力集中所致。The 2205 duplex stainless steel after solution-treated at 1050 ℃ was treated by aging treatment at 850 ℃ for 30 min,180 min,360 min respectively. The microstructure and fatigue crack propagation were studied by means of optical microscope,scanning electron microscopy and mechanical properties test,etc. The results show that σ phase is appeared along the boundary of α phase and γ phase,and also in the α phase after aging treatment at 850 ℃. The content of σ phase increases with the extension of aging time,and the σ phase becomes lamellar structure gradually. The tensile strength increases and the ductility decreases obviously after aging treatment. What＇s more,the steady fatigue crack propagation rates of the samples increase obviously and the fatigue crack threshold decreases with the extension of aging time. The main characteristics of fracture surfaces are cleavage fracture,and also secondary cracks can be observed near the σ phase,which is related from the precipitation of σ phase that causes the stress concentration.

关 键 词：双相不锈钢 时效处理 显微组织 疲劳裂纹扩展 

分 类 号：TG142.7[一般工业技术—材料科学与工程] TG113[金属学及工艺—金属材料]