11%Cr铁素体/马氏体钢蠕变前后的析出相研究
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摘要
利用透射电镜和能谱仪研究了一种11%Cr铁素体/马氏体钢在蠕变前后的析出相的类型、成分、形貌以及尺寸分布。结果表明,蠕变前钢中的析出相主要为富Cr的M_(23)C_6碳化物,富Nb/富Ta-Nb的MX碳化物,富Nb的MX碳氮化物。在600℃,150 MPa应力下蠕变1100 h后(未发生断裂),M_(23)C_6相的化学成分和尺寸几乎没有变化,Ta-Nb富集的MC析出相溶解,Nb富集的MX析出相内Nb元素含量少量上升,Ta与Cr元素含量下降。MX相的尺寸在蠕变后明显减小。此外,在蠕变后的钢中发现了(Fe,Cr)_2W型的Laves相和M_6C型的碳化物。
The type,composition,morphology and size distribution of precipitate phases in an 11%Cr ferritic/martensitic steel before and after creep were investigated by using transmission electron microscope with energy-dispersive X-ray spectroscopy.The results indicate that the main precipitate phases in the steel before creep are Cr-rich M_(23)C_6carbide,Nb-rich/Ta-Nb-rich MX carbides,and Nb-rich MX carbonitride.After a creep test at 600℃for 1100 h under 150 MPa(without break),the chemical composition and size of M_(23)C_6precipitates are almost unchanged;Ta-Nb-rich MC precipitates are dissolved;the Nb content slightly increases accompanied with decrease of Ta and Cr content in Nb-rich precipitates.The size of MX precipitates decreases obviously.In addition,(Fe,Cr)_2W Laves phase and M_6C carbide are observed in the steel after the creep test.
The type,composition,morphology and size distribution of precipitate phases in an 11%Cr ferritic/martensitic steel before and after creep were investigated by using transmission electron microscope with energy-dispersive X-ray spectroscopy.The results indicate that the main precipitate phases in the steel before creep are Cr-rich M_(23)C_6carbide,Nb-rich/Ta-Nb-rich MX carbides,and Nb-rich MX carbonitride.After a creep test at 600℃for 1100 h under 150 MPa(without break),the chemical composition and size of M_(23)C_6precipitates are almost unchanged;Ta-Nb-rich MC precipitates are dissolved;the Nb content slightly increases accompanied with decrease of Ta and Cr content in Nb-rich precipitates.The size of MX precipitates decreases obviously.In addition,(Fe,Cr)_2W Laves phase and M_6C carbide are observed in the steel after the creep test.
引文
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[2]Abe F,Igarashi M,Wanikawa S,et al.R&D of advanced ferritic steels for 650℃USC boilers[C]//PARSONS 2000:Fifth International Charles Parsons Turbine Conference.2000:129-142.
[3]季波,沈寅忠,崔凯.SAVE12钢蠕变前后的微观组织分析[J].材料热处理学报,2014,35(1):34-39.Ji Bo,Shen Yinzhong,Cui Kai.Microstructure of SAVE12 steel before and after creep[J].Transactions of Materials and Heat Treatment,2014,35(1):34-39.
[4]杜宝帅,王金海,刘睿,等.超温服役T91钢的显微组织与力学性能[J].金属热处理,2016,41(10):62-65.Du Baoshuai,Wang Jinhai,Liu Rui,et al.Microstructure and mechanical properties of T91 steel after exposure to abnormal high serving temperature[J].Heat Treatment of Metals,2016,41(10):62-65.
[5]孙国强,梁剑雄,刘振宝,等.回火温度对铁素体/马氏体双相不锈钢组织与性能的影响[J].金属热处理,2015,40(1):86-90.Sun Guoqiang,Liang Jianxiong,Liu Zhenbao,et al.Effect of tempering temperature on microstructure and properties of ferrite and martensite double phases stainless steel[J].Heat Treatment of Metals,2015,40(1):86-90.
[6]Sklenicˇka V,KucharˇováK,Svoboda M,et al.Long-term creep behavior of 9-12%Cr power plant steels[J].Materials Characterization,2003,51(1):35-48.
[7]Maruyama K,Sawada K,Jun-Ichi K.Strengthening mechanisms of creep resistant tempered martensitic steel[J].Transactions of the Iron and Steel Institute of Japan,2007,41(6):641-653.
[8]Rojas D,Garcia J,Prat O,et al.9%Cr heat resistant steels:Alloy design,microstructure evolution and creep response at 650℃[J].Materials Science and Engineering A,2011,528(15):5164-5176.
[9]Hkdh B.Design of ferritic creep-resistant steels[J].ISIJ International,2001,41(6):626-640.
[10]Aghajani A,Somsen C,Eggeler G.On the effect of long-term creep on the microstructure of a 12%chromium tempered martensite-ferritic steel[J].Acta Materialia,2009,57(17):5093-5106.
[11]Wey M Y,Sakuma T,Nishizawa T.Growth of alloy carbide particles in austenite[J].Transactions of the Japan Institute of Metals,1981,22(10):733-742.
[12]Abe F.Bainitic and martensitic creep-resistant steels[J].Current Opinion in Solid State and Materials Science,2004,8(3):305-311.
[13]Vodárek V.Stability of Z-phase and M6X in creep-resistant steels[J].Scripta Materialia,2012,66(9):678-681.
[14]Hald J.Microstructure and long-term creep properties of 9-12%Cr steels[J].International Journal of Pressure Vessels and Piping,2008,85(1):30-37.