含Al纳米贝氏体辙叉钢及其氢脆特性的第一性原理研究
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摘要
本文的目的是研究低合金含Al纳米贝氏体辙叉钢的微观组织、力学性能和耐磨性,以及含Al贝氏体钢氢脆现象的第一性原理的计算,为新型贝氏体辙叉钢的设计提供依据,同时从微观角度来研究钢中的氢脆现象。
本文以铁路上使用的贝氏体辙叉钢的成分为依据,在满足其各项性能指标的基础上,设计出含Al贝氏体辙叉钢用材。通过对其常规力学性能的测试,得出理想的正火-回火工艺。通过对组织和力学性能的分析,得出理想的等温淬火工艺。通过纳米压痕和纳米划痕实验,对不同热处理工艺下试样的微观力学性能进行研究。利用X射线衍射仪(XRD)、光学显微镜(OM)和透射电镜(TEM)对处理后试样的相组成和组织进行了研究,然后测定了不同热处理工艺下试样的干摩擦磨损性能。最后,利用第一性原理的密度泛函理论,研究了含Al贝氏体钢中的氢脆现象。
研究结果表明:本实验材料的最佳正火-回火工艺为:900℃奥氏体化0.5 h,350℃回火2 h。最佳等温淬火工艺为:920℃奥氏体化1 h,350℃等温淬火10 h。试样经正火-回火处理后,硬度值为63.2 HRC,韧性为46.9 J/cm2;经等温淬火处理后,硬度值为47 HRC,韧性为85.4 J/cm2;等温淬火处理后材料的性能满足铁路线路辙叉用钢标准。纳米划痕和压痕试验表明,等温淬火后试样的摩擦系数及微观硬度小于正火-回火处理后的试样,弹性模量大于正火-回火处理后的试样。在载荷为200 N、300 N,转速为200 r/min的条件下,等温淬火后试样的失重小于高速钢标准试样,其耐磨性较好。
通过第一性原理对不同铝、硅含量的铁单胞的形成能进行计算,结果表明,钢中可以用Al代替Si作为促进贝氏体转变过程的元素;氢原子进入铝作为置换原子的铁单胞后,体系的相对形成能值大于硅作为置换原子的铁单胞,这说明氢原子更加容易进入铁硅单胞,因此,含Al贝氏体钢比含Si贝氏体钢氢脆敏感性低。
The aim of the present dissertation is to investigate the microstructure, mechanical properties and the wear resistance of nano-bainite in low-alloyed Al-containing steels using for crossing, and to calculate hydrogen embrittlement in Al-containing bainitic steels with the first-principles, in order to provide basic data in designing the crossing of new kinds of bainitic steels, and to research hydrogen embrittlement in microcosmos.
In this paper, according to chemical constituents of crossing used in high-speed railways and with meeting demand of performance, we have designed the bainitic steels Al-contained used for crossing. With the test of the conventional mechanical properties, we find the optimal craft of normalizing and tempering; By the analysis of microstructure and mechanical properties, the craft of austempering can be gained. Through the nanoindentation and nanoscratch, we can study microcosmic properties of Al-containing bainitic steels. The phase composition and microstructural morphology were studied by X-ray diffractometer, optical microscope and transmission electron microscope. At last, the wear-resistance under the condition of dry sliding friction and wear is also measured.
The results show that,the optimal craft of normalizing and tempering is austenitized at 900℃for 0.5 h, then tempered at 350℃for 2 h;The craft of austempering is austenitized at 920℃for 1h, then isothermally quenched at 350℃for 10 h;After normalized and tempered, the rockwell hardness of specimen is 63.2 HRC, the impact toughness is 46.9 J/cm2; After austempered, the rockwell hardness of samples is 47 HRC, the impact toughness is 85.4 J/cm2; The mechanical properties of specimen austempered can meet the demand of the crossing in the railway. The results of the nanoindentation and nanoscratch have shown that friction coefficient and micro-hardness of specimen austempered are less than that normalized and tempered, and the elastic modulus of samples austempered is bigger than that normalized and tempered. With the load of 200 N or 300 N and the spin rates of 200 r/min, the mass loss of samples austempered is less than standard samples of high speed steel, which indicates that the wear-resistant of samples austempered is better.
According to first principles, we can calculate the formation energy of FCC structure of Fe with different content of Al or Si. The results show that Al by which replacing Si in steels can accelerate bainitic transformation; When H atom enters into the FCC structure of Fe with Al atom as replaceable atom, the relative formation energy of Fe-Al system is bigger than that of Fe-Si system, which indicates that it is more stabile that H atom enters into Fe-Si system. Consequently, the hydrogen embrittlement of bainitic steel containing Al is lower than that of bainitic steel containing Si.
本文以铁路上使用的贝氏体辙叉钢的成分为依据,在满足其各项性能指标的基础上,设计出含Al贝氏体辙叉钢用材。通过对其常规力学性能的测试,得出理想的正火-回火工艺。通过对组织和力学性能的分析,得出理想的等温淬火工艺。通过纳米压痕和纳米划痕实验,对不同热处理工艺下试样的微观力学性能进行研究。利用X射线衍射仪(XRD)、光学显微镜(OM)和透射电镜(TEM)对处理后试样的相组成和组织进行了研究,然后测定了不同热处理工艺下试样的干摩擦磨损性能。最后,利用第一性原理的密度泛函理论,研究了含Al贝氏体钢中的氢脆现象。
研究结果表明:本实验材料的最佳正火-回火工艺为:900℃奥氏体化0.5 h,350℃回火2 h。最佳等温淬火工艺为:920℃奥氏体化1 h,350℃等温淬火10 h。试样经正火-回火处理后,硬度值为63.2 HRC,韧性为46.9 J/cm2;经等温淬火处理后,硬度值为47 HRC,韧性为85.4 J/cm2;等温淬火处理后材料的性能满足铁路线路辙叉用钢标准。纳米划痕和压痕试验表明,等温淬火后试样的摩擦系数及微观硬度小于正火-回火处理后的试样,弹性模量大于正火-回火处理后的试样。在载荷为200 N、300 N,转速为200 r/min的条件下,等温淬火后试样的失重小于高速钢标准试样,其耐磨性较好。
通过第一性原理对不同铝、硅含量的铁单胞的形成能进行计算,结果表明,钢中可以用Al代替Si作为促进贝氏体转变过程的元素;氢原子进入铝作为置换原子的铁单胞后,体系的相对形成能值大于硅作为置换原子的铁单胞,这说明氢原子更加容易进入铁硅单胞,因此,含Al贝氏体钢比含Si贝氏体钢氢脆敏感性低。
The aim of the present dissertation is to investigate the microstructure, mechanical properties and the wear resistance of nano-bainite in low-alloyed Al-containing steels using for crossing, and to calculate hydrogen embrittlement in Al-containing bainitic steels with the first-principles, in order to provide basic data in designing the crossing of new kinds of bainitic steels, and to research hydrogen embrittlement in microcosmos.
In this paper, according to chemical constituents of crossing used in high-speed railways and with meeting demand of performance, we have designed the bainitic steels Al-contained used for crossing. With the test of the conventional mechanical properties, we find the optimal craft of normalizing and tempering; By the analysis of microstructure and mechanical properties, the craft of austempering can be gained. Through the nanoindentation and nanoscratch, we can study microcosmic properties of Al-containing bainitic steels. The phase composition and microstructural morphology were studied by X-ray diffractometer, optical microscope and transmission electron microscope. At last, the wear-resistance under the condition of dry sliding friction and wear is also measured.
The results show that,the optimal craft of normalizing and tempering is austenitized at 900℃for 0.5 h, then tempered at 350℃for 2 h;The craft of austempering is austenitized at 920℃for 1h, then isothermally quenched at 350℃for 10 h;After normalized and tempered, the rockwell hardness of specimen is 63.2 HRC, the impact toughness is 46.9 J/cm2; After austempered, the rockwell hardness of samples is 47 HRC, the impact toughness is 85.4 J/cm2; The mechanical properties of specimen austempered can meet the demand of the crossing in the railway. The results of the nanoindentation and nanoscratch have shown that friction coefficient and micro-hardness of specimen austempered are less than that normalized and tempered, and the elastic modulus of samples austempered is bigger than that normalized and tempered. With the load of 200 N or 300 N and the spin rates of 200 r/min, the mass loss of samples austempered is less than standard samples of high speed steel, which indicates that the wear-resistant of samples austempered is better.
According to first principles, we can calculate the formation energy of FCC structure of Fe with different content of Al or Si. The results show that Al by which replacing Si in steels can accelerate bainitic transformation; When H atom enters into the FCC structure of Fe with Al atom as replaceable atom, the relative formation energy of Fe-Al system is bigger than that of Fe-Si system, which indicates that it is more stabile that H atom enters into Fe-Si system. Consequently, the hydrogen embrittlement of bainitic steel containing Al is lower than that of bainitic steel containing Si.
引文
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2方鸿生,郑燕康,黄进峰等.我国贝氏体钢的前景.金属热处理,1998,(7):11-14.
3 F C Zhang, B Lv, B T Hu,, et al. Flash butt welding of high manganese steel crossing and carbon steel rail. Materials Science and Engineering A. 2007,454—455:288-292.
4 D. R. Pendleton, K. Compton, E. G. Jones. Welded and cast-cetre crossings accepted after trial. Railway Gazette International, 1986(3):176-177.
5 K Sawley, M Scholl. The Development of Bainitic Steels for Rails. MWSP CONF. 1997,(39):1007-1014.
6, J Sun. Advanced rail steels: Investigating the bainitic option. Railway Track&Structures, 1997,(3):22-27.
7 D R Pendleton, K. Compton, E G Jones. Welded and cast-cetre crossings accepted after trial. Railway Gazette International, 1986(3): 176-177.
8 D Davis, M Scholl, S Huseyin. Development of bainitic frogs for HAL service. Railway Track & Structures, 1997(12): 14-16.
9 D D,Davis, D G S Guillen, D Charity. An update on revenue service tests of bainitic steel rail crossing diamonds. Railway Track and Structures, 2003, 99(1): 15-17.
10 Y Satoh, Kasiwaya, Kenji, et al. Development of anti-darkspot bainitic steel rail. Quarterly Report of RTRI ,1999, 2: 86-91.
11 BWG, Leaders in Modern Track Technology, 18.
12方鸿生,陈颜堂,郑燕康,等.铁道辙叉专用超强高韧可焊接空冷鸿康贝氏体钢,CN98124899.3。
13方鸿生,郑燕康,白秉哲,杨志刚,刘东雨.中低碳锰系空冷贝氏体钢,CN03150092.7.
14常开地,顾家琳,方鸿生,白秉哲,杨志刚,韦东远.新型1500MPa级高强钢的氢脆敏感性研究,金属热处理2002; 27(3) 8-11。
15栾道成,魏成富.速准高速铁路道叉高性能耐磨钢:中国, 12095.4.
16张福成,郑炀曾,吕博.铁路辙叉专用含钨铝贝氏体锻钢:中国, 200610048109.8. 2007-01-31.
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18 F C Zhang, C L Zheng, B Lv, et al. Effects of Hydrogen on the Properties of Bainite Steel Crossing. Engineering Failure Analysis, 2008 .
19康大韬,叶国斌.大型锻件材料及热处理.龙门书局, 1998,114-159.
20 M. R. Louthan. Material Science and Engineering.ASM, 1972, (10):357-368.
21 R. Kerr, F. Solaria, I. M. Berstein, A. W. Thompson. Mirostructural effects on the stress corrosion cracking behavior of medium and high strength steels. Metall. Trans., 1987, (18A):1011-1022.
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23常开第,顾家琳,方鸿生等.贝氏体/马氏体复相高强钢中的氢陷阱.金属热处理, 2003,28(3):20-23.
24褚武扬,李世琼,肖纪美等.氢致滞后塑性变形机理研究.金属学报, 1982, (16):47.
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32 Z.M. Xu. Influence of Ce and A1 on Modularization of Eutectic in Austenite-bainiteSteel. Mater. Res. Bull., 2000, 35:1261
33 C. Garcia-Mateo, F.G. Caballero, H.K.D.H. Bhadeshia. Acceleration of Low-temperature Bainite. ISIJ Int.,2003,43:1821-1825
34黄维刚,徐蓉,方鸿生等.中低碳含Si空冷贝氏体钢的冲击韧度.钢铁研究学报, 1997, 9(2):31-43
35黄维刚,方鸿生,郑燕康. Si和少量Mo对Mn2B系贝氏体钢转变动力学的影响.金属热处理, 1997, (10):25-28
36文翠娥,孙培祯,谢长生等. Si对GD钢贝氏体组织形态及力学性能的影响.钢铁研究学报, 1993, 5(3):47-52
37张明星,康沫狂. Si对低碳贝氏体钢组织和性能的影响.金属学报, 1993, 29(1):6-10
38 Q.C. Jiang, et al. Bionics Growth Mechanism of Nodular Eutectic in As-cast Manganese Steel. Science and Technology of Advanced Materials, 2001, 2(1): 253-255
39郭继伟,阮芳,刘冬梅.碳和Si含量及热处理参数对贝氏体钢性能的影响.机械工程师, 2003,(3):9-14
40陈颜堂,方鸿生,白秉哲等. Si对高强度高韧性贝氏体钢冲击磨损性能的影响.金属热处理, 2001, 26(8):5-7
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2方鸿生,郑燕康,黄进峰等.我国贝氏体钢的前景.金属热处理,1998,(7):11-14.
3 F C Zhang, B Lv, B T Hu,, et al. Flash butt welding of high manganese steel crossing and carbon steel rail. Materials Science and Engineering A. 2007,454—455:288-292.
4 D. R. Pendleton, K. Compton, E. G. Jones. Welded and cast-cetre crossings accepted after trial. Railway Gazette International, 1986(3):176-177.
5 K Sawley, M Scholl. The Development of Bainitic Steels for Rails. MWSP CONF. 1997,(39):1007-1014.
6, J Sun. Advanced rail steels: Investigating the bainitic option. Railway Track&Structures, 1997,(3):22-27.
7 D R Pendleton, K. Compton, E G Jones. Welded and cast-cetre crossings accepted after trial. Railway Gazette International, 1986(3): 176-177.
8 D Davis, M Scholl, S Huseyin. Development of bainitic frogs for HAL service. Railway Track & Structures, 1997(12): 14-16.
9 D D,Davis, D G S Guillen, D Charity. An update on revenue service tests of bainitic steel rail crossing diamonds. Railway Track and Structures, 2003, 99(1): 15-17.
10 Y Satoh, Kasiwaya, Kenji, et al. Development of anti-darkspot bainitic steel rail. Quarterly Report of RTRI ,1999, 2: 86-91.
11 BWG, Leaders in Modern Track Technology, 18.
12方鸿生,陈颜堂,郑燕康,等.铁道辙叉专用超强高韧可焊接空冷鸿康贝氏体钢,CN98124899.3。
13方鸿生,郑燕康,白秉哲,杨志刚,刘东雨.中低碳锰系空冷贝氏体钢,CN03150092.7.
14常开地,顾家琳,方鸿生,白秉哲,杨志刚,韦东远.新型1500MPa级高强钢的氢脆敏感性研究,金属热处理2002; 27(3) 8-11。
15栾道成,魏成富.速准高速铁路道叉高性能耐磨钢:中国, 12095.4.
16张福成,郑炀曾,吕博.铁路辙叉专用含钨铝贝氏体锻钢:中国, 200610048109.8. 2007-01-31.
17郑春雷,张福成,吕博,等.辙叉用贝氏体钢的氢脆特性及去氢退火工艺.材料热处理学报, 2008, 29(2): 71-75.
18 F C Zhang, C L Zheng, B Lv, et al. Effects of Hydrogen on the Properties of Bainite Steel Crossing. Engineering Failure Analysis, 2008 .
19康大韬,叶国斌.大型锻件材料及热处理.龙门书局, 1998,114-159.
20 M. R. Louthan. Material Science and Engineering.ASM, 1972, (10):357-368.
21 R. Kerr, F. Solaria, I. M. Berstein, A. W. Thompson. Mirostructural effects on the stress corrosion cracking behavior of medium and high strength steels. Metall. Trans., 1987, (18A):1011-1022.
22徐坚,戴新民,夏雨筑.腐蚀金属学及耐腐蚀金属材料.浙江:浙江科技出版社, 1981,77.
23常开第,顾家琳,方鸿生等.贝氏体/马氏体复相高强钢中的氢陷阱.金属热处理, 2003,28(3):20-23.
24褚武扬,李世琼,肖纪美等.氢致滞后塑性变形机理研究.金属学报, 1982, (16):47.
25 R. A. Mccoy, Hydrogen in Metals, I. M. Bernstein, A. W. Thompson, eds., ASM, 1974, 169.
26褚武扬.氢损伤和氢滞后断裂,冶金工业出版社, 1988, 139-259.
27 M. L. Cohen. Phys. Rev. B,1985,32 (12):7988 -7990
28谢希德,陆栋.固体能带理论.上海:复旦大学出版社,1998:1-26
29 R. M. Weeny. Method of Molecular Quantum Mechanics. London: Academic Press,1992:40-65
30徐光宪,黎乐民,王德民.量子化学-基本原理和从头计算法.北京:科学出版社,1985: 1-35
31 R. Hoffmann.固体与表面:一位化学家关于扩展结构中成键作用的见解.郭洪猷,李静.北京:化学工业出版社1996:1-66
32 Z.M. Xu. Influence of Ce and A1 on Modularization of Eutectic in Austenite-bainiteSteel. Mater. Res. Bull., 2000, 35:1261
33 C. Garcia-Mateo, F.G. Caballero, H.K.D.H. Bhadeshia. Acceleration of Low-temperature Bainite. ISIJ Int.,2003,43:1821-1825
34黄维刚,徐蓉,方鸿生等.中低碳含Si空冷贝氏体钢的冲击韧度.钢铁研究学报, 1997, 9(2):31-43
35黄维刚,方鸿生,郑燕康. Si和少量Mo对Mn2B系贝氏体钢转变动力学的影响.金属热处理, 1997, (10):25-28
36文翠娥,孙培祯,谢长生等. Si对GD钢贝氏体组织形态及力学性能的影响.钢铁研究学报, 1993, 5(3):47-52
37张明星,康沫狂. Si对低碳贝氏体钢组织和性能的影响.金属学报, 1993, 29(1):6-10
38 Q.C. Jiang, et al. Bionics Growth Mechanism of Nodular Eutectic in As-cast Manganese Steel. Science and Technology of Advanced Materials, 2001, 2(1): 253-255
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