Please wait a minute...
金属学报  2018, Vol. 54 Issue (11): 1705-1714    DOI: 10.11900/0412.1961.2018.00361
  力学性能 本期目录 | 过刊浏览 |
新型25Cr-20Ni奥氏体耐热不锈钢750 ℃持久实验过程中析出相演变
胡国栋1,2, 王培1, 李殿中1(), 李依依1
1 中国科学院金属研究所 沈阳 110016
2 中国科学技术大学材料科学与工程学院 沈阳 110016
Precipitate Evolution in a Modified 25Cr-20Ni Austenitic Heat Resistant Stainless Steel During CreepRupture Test at 750 ℃
Guodong HU1,2, Pei WANG1, Dianzhong LI1(), Yiyi LI1
1 Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
2 School of Materials Science and Engineering, University of Science and Technology of China, Shenyang 110016, China
全文: PDF(9763 KB)   HTML

研究了一种新型25Cr-20Ni奥氏体耐热不锈钢在750 ℃不同拉应力持久实验中析出相演变及其对性能的影响。结果表明,当持久应力为180 MPa时,持久寿命为32.6 h,析出相包括M23C6和(Nb, V)(C, N)相。其中M23C6主要分布在晶界位置,(Nb, V)(C, N)相在晶内弥散析出。当持久应力为150和120 MPa时,随着持久时间延长至98.1 h以上,晶界位置的M23C6发生长大和Ostwald熟化,但(Nb, V)(C, N)相具有较好的尺寸稳定性。同时,在持久应力为120 MPa条件下,组织中出现σ相。σ相首先在晶界位置析出,当持久应力为100 MPa时,随持久时间延长至752.3 h,σ相也会在晶内析出。研究还发现,大量σ相依附于(Nb, V)(C, N)相析出,这是由于(Nb, V)(C, N)相的析出导致附近奥氏体基体中局部位置C和N元素含量减少,从而促进了σ相的形核。不同应力条件下试样断裂方式均为沿晶断裂,当持久时间较短时,裂纹在晶界M23C6处产生,引起沿晶开裂。随着持久时间延长,σ相在晶界析出后,裂纹更容易在晶界σ相处产生,导致持久延伸率随持久寿命延长而减小。

关键词 奥氏体耐热不锈钢持久析出相演变σMX    

25Cr-20Ni austenitic heat resistant stainless steels are widely used as structural materials in nuclear industries and power plants for their excellent corrosion resistance and creep properties at elevated temperature. It is generally accepted that the precipitation during creep is a key factor influencing the creep properties. However, the evolution of precipitates is complicated due to the interaction of the alloy elements. To investigate the precipitation behaviors, a modified 25Cr-20Ni austenitic heat resistant stainless steel has been crept at 750 ℃ under different stresses varying from 100 MPa to 180 MPa. The microstructure observation indicates that M23C6 and (Nb, V)(C, N) precipitates are formed during 32.6 h creeping deformation under 180 MPa. M23C6 precipitates are mainly generated at grain boundaries and (Nb, V)(C, N) particles are dispersively distributed in austenitic matrix. The grain boundary M23C6 carbides are significantly coarsened and Ostwald ripening process happens during 98.1 h creeping deformation under the stress of 150 MPa and 353.0 h creeping deformation under stress of 120 MPa, while (Nb, V)(C, N) carbonitrides show high dimensional stability. With the creep rupture time further prolonging to 353.0 h and 752.3 h under the creep stress of 120 and 100 MPa, respectively, σ-phases are generated first at grain boundaries and then at inner grains. Meanwhile, large amounts of σ-phases are formed around (Nb, V)(C, N) particles, indicating the σ-phase precipitation is accelerated by (Nb, V)(C, N) carbonitrides. Composition analysis and thermodynamic calculation are subsequently performed to elucidate the precipitation mechanism of σ-phase. Carbon and nitrogen depleted zone is detected at the interface between (Nb, V)(C, N) precipitates and austenitic matrix. A correlation between σ-phase and C/N contents has been calculated by Thermo-Calc, which shows that the mass fraction of σ-phase increases with the decreasing C/N contents. According to the thermodynamic calculations and experimental results, it is reasonably inferred that the formation of σ-phase is induced by the carbon and nitrogen depletion in austenitic matrix. Additionally, the fracture surfaces of creep specimens show intergranular fracture under all creep stresses. When the creep time is comparatively short, cracks are inclined to propagate along grain boundaries owing to the low cohesion between grain boundary M23C6 precipitates and austenitic matrix, resulting in intergranular creep fracture. With the precipitation of σ-phase at grain boundaries after long time creep, the cracks are primarily generated from σ-phase, further deteriorating the creep elongation.

Key wordsaustenitic heat resistant stainless steel    creep rupture    precipitate evolution    σ-phase    MX
收稿日期: 2018-08-01     
ZTFLH:  TG142.1  

作者简介 胡国栋,男,1991年生,博士生


胡国栋, 王培, 李殿中, 李依依. 新型25Cr-20Ni奥氏体耐热不锈钢750 ℃持久实验过程中析出相演变[J]. 金属学报, 2018, 54(11): 1705-1714.
Guodong HU, Pei WANG, Dianzhong LI, Yiyi LI. Precipitate Evolution in a Modified 25Cr-20Ni Austenitic Heat Resistant Stainless Steel During CreepRupture Test at 750 ℃. Acta Metall Sin, 2018, 54(11): 1705-1714.

链接本文:      或

图1  新型25Cr-20Ni奥氏体耐热不锈钢固溶态微观组织的SEM像和EDS分析
图2  新型25Cr-20Ni奥氏体耐热不锈钢在750 ℃、180 MPa和150 MPa应力条件下持久实验后微观组织的SEM像和晶界处析出相的TEM像以及SAED花样
图3  新型25Cr-20Ni奥氏体耐热不锈钢在750 ℃、120 MPa和100 MPa应力条件下持久实验后微观组织的SEM像和晶界处析出相的TEM像
图4  新型25Cr-20Ni奥氏体耐热不锈钢持久实验后晶内析出相的TEM像和SAED花样
图5  新型25Cr-20Ni奥氏体耐热不锈钢在750 ℃、100 MPa持久实验后σ相的TEM像和SAED花样
图6  新型25Cr-20Ni奥氏体耐热不锈钢750 ℃、100 MPa持久试样中析出相的TEM像及周围基体元素分布的EDS分析
图7  C、N含量对σ相含量影响以及不同温度下相平衡分数和固溶C、N含量的Thermo-calc热力学计算
图8  750 ℃不同应力条件下新型25Cr-20Ni奥氏体耐热不锈钢的蠕变应变-时间曲线
图9  新型25Cr-20Ni奥氏体耐热不锈钢持久试样断口形貌
图10  新型25Cr-20Ni奥氏体耐热不锈钢持久试样纵剖面裂纹扩展形貌
[1] Zhang Z, Hu Z F, Tu H Y, et al.Microstructure evolution in HR3C austenitic steel during long-term creep at 650 ℃[J]. Mater. Sci. Eng., 2017, A681: 74
[2] Bai X, Pan J, Chen G, et al.Effect of high temperature aging on microstructure and mechanical properties of HR3C heat resistant steel[J]. Mater. Sci. Technol., 2014, 30: 205
[3] Cao T S, Fang X D, Cheng C Q, et al.Creep behavior of two kinds of HR3C heat resistant steels based on stress relaxation tests[J]. Acta Metall. Sin., 2014, 50: 1343(曹铁山, 方旭东, 程从前等. 应力松弛方法研究2种HR3C耐热钢的高温蠕变行为[J]. 金属学报, 2014, 50: 1343)
[4] Fang Y Y, Zhao J, Li X N.Precipitates in HR3C steel aged at high temperature[J]. Acta Metall. Sin., 2010, 46: 844(方园园, 赵杰, 李晓娜. HR3C钢高温时效过程中的析出相[J]. 金属学报, 2010, 46: 844)
[5] Yang Y H, Zhu K H, Wang Q J, et al.Microstructural evolution and the effect on hardness and plasticity of S31042 heat-resistant steel during creep[J]. Mater. Sci. Eng., 2014, A608: 164
[6] Sourmail T.Precipitation in creep resistant austenitic stainless steels[J]. Mater. Sci. Technol., 2001, 17: 1
[7] Peng B C, Zhang H X, Hong J, et al.Effect of aging on the impact toughness of 25Cr-20Ni-Nb-N steel[J]. Mater. Sci. Eng., 2010, A527: 1957
[8] Tavares S S M, Moura V, da Costa V C, et al. Microstructural changes and corrosion resistance of AISI 310S steel exposed to 600-800 ℃[J]. Mater. Charact., 2009, 60: 573
[9] Padilha A F, Rios P R.Decomposition of austenite in austenitic stainless steels[J]. ISIJ Int., 2002, 42: 325
[10] K?llqvist J, Andrén H O.Microanalysis of a stabilised austenitic stainless steel after long term ageing[J]. Mater. Sci. Eng., 1999, A270: 27
[11] Park D B, Huh M Y, Jung W S, et al.Effect of vanadium addition on the creep resistance of 18Cr9Ni3CuNbN austenitic stainless heat resistant steel[J]. J. Alloys Compd., 2013, 574: 532
[12] Erneman J, Schwind M, Andrén H O, et al.The evolution of primary and secondary niobium carbonitrides in AISI 347 stainless steel during manufacturing and long-term ageing[J]. Acta Mater., 2006, 54: 67
[13] Ni Z F, Sun Y S, Xue F, et al.Study on fabrication, microstructure and properties of in situ TiC particle on dispersion-strengthened 304 stainless steel[J]. Acta Metall. Sin., 2010, 46: 935(倪自飞, 孙扬善, 薛烽等. 原位TiC颗粒弥散强化304不锈钢的制备及组织性能研究[J]. 金属学报, 2010, 46: 935)
[14] Chastell D J, Flewitt P E J. The formation of the σ-phase during long term high temperature creep of type 316 austenitic stainless steel[J]. Mater. Sci. Eng., 1979, A38: 153
[15] Anburaj J, Nazirudeen S S M, Narayanan R, et al. Ageing of forged superaustenitic stainless steel: Precipitate phases and mechanical properties[J]. Mater. Sci. Eng., 2012, A535: 99
[16] Di Gianfrancesco A.Materials for Ultra-Supercritical and Advanced Ultra-Supercritical Power Plants [M]. Duxford: Woodhead Publishing, 2017: 376
[17] Hsieh C C, Wu W T.Overview of intermetallic sigma (σ) phase precipitation in stainless steels[J]. ISRN Metall., 2012, 2012: 732471
[18] Schwind M, K?llqvist J, Nilsson J O, et al.σ-phase precipitation in stabilized austenitic stainless steels[J]. Acta Mater., 2000, 48: 2473
[19] Garcés G R, Le Coze J, Garin J L, et al.σ-phase precipitation in two heat-resistant steels-influence of carbides and microstructure[J]. Scr. Mater., 2004, 50: 651
[20] Barcik J.Mechanism of σ-phase precipitation in Cr-Ni austenitic steels[J]. Mater. Sci. Technol., 1988, 4: 5
[21] Lee T H, Oh C S, Lee C G, et al.Precipitation of σ-phase in high-nitrogen austenitic 18Cr-18Mn-2Mo-0.9N stainless steel during isothermal aging[J]. Scr. Mater., 2004, 50: 1325
[22] Minami Y, Kimura H, Ihara Y.Microstructural changes in austenitic stainless steels during long-term aging[J]. Mater. Sci. Technol., 1986, 2: 795
[23] West D, Hulance J, Higginson R L, et al.σ-phase precipitation in 347HFG stainless steel[J]. Mater. Sci. Technol., 2013, 29: 835
[24] Perron A, Toffolon-Masclet C, Ledoux X, et al.Understanding sigma-phase precipitation in a stabilized austenitic stainless steel (316Nb) through complementary CALPHAD-based and experimental investigations[J]. Acta Mater., 2014, 79: 16
[25] Kaneko K, Fukunaga T, Yamada K, et al.Formation of M23C6-type precipitates and chromium-depleted zones in austenite stainless steel[J]. Scr. Mater., 2011, 65: 509
[26] Liu Q D, Chu Y L, Peng J C, et al.3D atom probe characterazation of alloy carbides in tempering martenite III. Coarsening[J] Acta Metall. Sin., 2009, 45: 1297(刘庆冬, 褚于良, 彭剑超等. 回火马氏体中合金碳化物的3D原子探针表征 Ⅲ. 粗化[J]. 金属学报, 2009, 45: 1297)
[27] Shinohara K, Seo T, Kumada K.Recrystallization and sigma phase formation as concurrent and interacting phenomena in 25%Cr-20%Ni steel[J]. Trans. Jpn. Inst. Met., 1979, 20: 713
[28] Wang Y Q, Yang B, Li N, et al.Embrittlement of σ phase in stainless steel for primary coolant pipes of nuclear power plant[J]. Acta Metall. Sin., 2015, 52: 17(王永强, 杨滨, 李娜等. σ相在核电一回路主管道不锈钢中的脆化机理[J]. 金属学报, 2015, 52: 17)
[1] 曹铁山, 赵津艺, 程从前, 孟宪明, 赵杰. 冷变形和固溶温度对HR3C钢中σ相析出行为的影响[J]. 金属学报, 2020, 56(5): 673-682.
[2] 姚小飞, 魏敬鹏, 吕煜坤, 李田野. (CoCrFeMnNi)97.02Mo2.98高熵合金σ相析出演变及力学性能[J]. 金属学报, 2020, 56(5): 769-775.
[3] 唐文书,肖俊峰,李永君,张炯,高斯峰,南晴. 再热恢复处理对蠕变损伤定向凝固高温合金γ′相的影响[J]. 金属学报, 2019, 55(5): 601-610.
[4] 李彦默, 刘晨曦, 余黎明, 李会军, 王祖敏, 刘永长, 李文亚. 高温时效对S31042钢线性摩擦焊接头组织和力学性能的影响[J]. 金属学报, 2018, 54(7): 981-990.
[5] 童锦艳,冯微,付超,郑运荣,冯强. GH4033合金短时超温后的显微组织损伤及力学性能[J]. 金属学报, 2015, 51(10): 1242-1252.
[6] 赵云松,张剑,骆宇时,唐定中,冯强. Hf对第二代镍基单晶高温合金DD11高温低应力持久性能的影响[J]. 金属学报, 2015, 51(10): 1261-1272.
[7] 林惠文,刘纪德,周亦胄,金涛,孙晓峰. Pt对镍基单晶高温合金持久性能的影响[J]. 金属学报, 2015, 51(1): 77-84.
[8] 杨金侠, 孙元, 金涛, 孙晓峰, 胡壮麒. 一种细晶铸造镍基高温合金的组织与力学性能*[J]. 金属学报, 2014, 50(7): 839-844.
[9] 余竹焕, 刘林. C对单晶高温合金持久性能的影响*[J]. 金属学报, 2014, 50(7): 854-862.
[10] 熊继春, 李嘉荣, 孙凤礼, 刘世忠, 韩梅. 单晶高温合金DD6再结晶组织及其对持久性能的影响*[J]. 金属学报, 2014, 50(6): 737-743.
[11] 周德强, 刘雄军, 吴渊, 王辉, 吕昭平. 新型奥氏体耐热不锈钢再结晶行为及其对力学性能的影响[J]. 金属学报, 2014, 50(10): 1217-1223.
[12] 曹亮, 周亦胄, 金涛, 孙晓峰. 晶界角度对一种镍基双晶高温合金持久性能的影响*[J]. 金属学报, 2014, 50(1): 11-18.
[13] 肖旋,赵海强,王常帅,郭永安,郭建亭,周兰章. B和P对GH984合金组织和力学性能的影响[J]. 金属学报, 2013, 29(4): 421-427.
[14] 杨金侠,李金国,王猛,王延辉,金涛,孙晓峰. 热处理工艺对一种新型铸造镍基高温合金的组织和性能影响[J]. 金属学报, 2012, 48(6): 654-660.
[15] 彭志方,党莹樱,彭芳芳. C和Nb含量对TP347HFG钢在650 ℃析出相参量和持久寿命的影响[J]. 金属学报, 2012, 48(4): 450-454.