摘要
采用RDL100型电子高温蠕变试验机测试了新型Cr18Ni9Nb Ti N奥氏体不锈钢在650℃不同应力下的蠕变性能。利用SEM、TEM及EDS等观察分析了220 MPa下不同蠕变阶段的组织形貌。结果表明,蠕变初期,晶内位错密度急剧增加,位错发生缠结,晶内有细小的Nb N相弥散析出;稳态蠕变阶段,位错形成网状结构,晶内有Ti N颗粒析出,链状(Cr,Fe)23C6沿晶界析出,位错网和析出的第二相共同降低了位错可动性,改善了合金抗蠕变性能;加速蠕变阶段,大量扩展位错出现,延长了蠕变寿命。Cr18Ni9Nb Ti N钢蠕变断裂属于沿晶脆性断裂,晶界处发现部分(Cr,Fe)23C6剥落,三叉晶界处发现楔形裂纹。
Creep property of a novel Cr18Ni9 Nb Ti N austenitic stainless steel at 650 ℃ and different stresses was investigated by RDL100 high temperature electrical creep machine. Microstructure of the Cr18Ni9 Nb Ti N steel at different creep stage under 220 MPa were observed and analyzed by using SEM,TEM and EDS. The results show that during initial-state creep stage,intracrystalline dislocation density increases dramatically,tangled dislocation is found,tiny Nb N precipitates disperse distribute within the grain. During steady-state creep stage,dislocations form reticular structure,Ti N particles separates out from the grains,chain（ Cr,Fe）23C6precipitates along grain boundaries,reticular dislocation and precipitated second phase not only reduce the mobility of dislocation together,but also improve the creep resistance of the alloy. During accelerate-state creep stage,a large number of extended dislocations appeared which extend the creep life of the steel. Creep rupture of Cr18Ni9 Nb Ti N steel belongs to intergranular brittle fracture,some of（ Cr,Fe）23C6precipitates on the grain boundary exfoliated,wedge cracks are found at trigeminal grain boundary.
出处
《金属热处理》
CAS
CSCD
北大核心
2016年第3期114-118,共5页
Heat Treatment of Metals
基金
国家高技术研究发展计划(863计划)(2012AA03A501)
江苏省产学研联合创新资金-前瞻性联合研究项目(BY2012169)
江苏省2014年度普通高校研究生科研创新计划项目(KYLX-1027)
