定向凝固Ti-（50，52）at.%Al合金组织演化规律研究
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摘要
本文以Ti-Al合金为研究对象,选取Ti-50at.%Al,Ti-52at.%Al两组合金成分,在1μm/s~35μm/s的凝固速度区间内开展了定向凝固实验研究。通过光学金相,电子显微分析技术对从初始过渡到稳态凝固组织的演化规律及其对后续固态相变形成的片层结构取向的关系进行了研究。
研究结果表明:随着生长速度的加大,固液界面形态由平到胞、枝再到等轴晶变化;对于Ti-50at.%Al合金,在低速条件下以α单相凝固,随着生长速度的加大,α胞、枝之间出现少量的γ相,α相在凝固过程中始终占优;对于Ti-52at.%Al合金,其凝固组织由α和γ两相组成,随着生长速度的增大,凝固组织由平面α和岛状γ相转变成α和γ胞状共生,再转变成枝晶α和枝晶间γ相,γ相的体积含量逐渐增加,主要由液相直接凝固得到;在较高的生长速度条件下,α初生相以枝晶形态生长,α相与液相的接触面积加大,促进了L +α→γ包晶反应,α枝晶臂被消耗形成细小的α晶粒。
α相在后续的固态相变过程中转变成α2/γ片层组织。在通常情况下,由于α母相与片层组织中γ相确定的位向关系,得到片层取向与生长方向垂直的α2/γ片层组织。但是当α相以铸态晶粒为形核衬底时,α2/γ片层保留了原始铸态晶粒内的片层取向。同时在高的生长速度条件下,定向凝固过程中形成了大量枝晶主干偏离热流方向的α枝晶,当熔体前方新形成的枝晶以之为形核衬底时,保留了原有枝晶内的片层取向。因此可以利用母体合金本身“自引晶”来控制片层取向。
In this paper, Ti-Al alloys with two compositions of Ti-50at.%Al and Ti-52at.%Al were studied with growth rate range from 1μm/s to 35μm/s. The solidification structure evolution from initial transition region to steady state region and its influence on theα2/γlamellar orientation were analyzed.
The results show that the interface with planar front evolves to cell, dendrite and equiaxed dendrite with the increase of growth rate. Ti-50at.%Al alloy solidifies as singleαphase at low growth rate. As the growth rate increases, there forms a littleγat intercells or interdendrites.αphase dominates during the whole solidification process. Ti-52at.%Al alloy solidifies asαandγphases. With the increase of growth rate, the planarαand islandγphase evolves toαandγcellular coupled growth, then toαdendrites and interdendriteγ.γphase is mainly obtained by directly solidified liquid and its volume fraction increases as growth rate increases. At high growth rate, primaryαphase grows as dendrites and contacts more liquid, which contributes to the L +α→γperitectic reaction. During the process,αdendrites are consumed to form fineαgrains.
αphase transforms toα2/γlamellar in subsequent solid phase transformation. In general, the lamellar orientation is perpendicular to growth direction because of the definite orientation betweenαandγphases. Whenαphase nucleates on the cast grains, the lamellar orientation within cast grains is maintained. At high growth rate, there forms manyαgrains whose growth direction deviate from heat flow. When new dendrites nucleate on those grains, the lamellar orientation is maintained. Thus, it is possible to develop“self seeding”technology to control the lamellar orientation.
研究结果表明:随着生长速度的加大,固液界面形态由平到胞、枝再到等轴晶变化;对于Ti-50at.%Al合金,在低速条件下以α单相凝固,随着生长速度的加大,α胞、枝之间出现少量的γ相,α相在凝固过程中始终占优;对于Ti-52at.%Al合金,其凝固组织由α和γ两相组成,随着生长速度的增大,凝固组织由平面α和岛状γ相转变成α和γ胞状共生,再转变成枝晶α和枝晶间γ相,γ相的体积含量逐渐增加,主要由液相直接凝固得到;在较高的生长速度条件下,α初生相以枝晶形态生长,α相与液相的接触面积加大,促进了L +α→γ包晶反应,α枝晶臂被消耗形成细小的α晶粒。
α相在后续的固态相变过程中转变成α2/γ片层组织。在通常情况下,由于α母相与片层组织中γ相确定的位向关系,得到片层取向与生长方向垂直的α2/γ片层组织。但是当α相以铸态晶粒为形核衬底时,α2/γ片层保留了原始铸态晶粒内的片层取向。同时在高的生长速度条件下,定向凝固过程中形成了大量枝晶主干偏离热流方向的α枝晶,当熔体前方新形成的枝晶以之为形核衬底时,保留了原有枝晶内的片层取向。因此可以利用母体合金本身“自引晶”来控制片层取向。
In this paper, Ti-Al alloys with two compositions of Ti-50at.%Al and Ti-52at.%Al were studied with growth rate range from 1μm/s to 35μm/s. The solidification structure evolution from initial transition region to steady state region and its influence on theα2/γlamellar orientation were analyzed.
The results show that the interface with planar front evolves to cell, dendrite and equiaxed dendrite with the increase of growth rate. Ti-50at.%Al alloy solidifies as singleαphase at low growth rate. As the growth rate increases, there forms a littleγat intercells or interdendrites.αphase dominates during the whole solidification process. Ti-52at.%Al alloy solidifies asαandγphases. With the increase of growth rate, the planarαand islandγphase evolves toαandγcellular coupled growth, then toαdendrites and interdendriteγ.γphase is mainly obtained by directly solidified liquid and its volume fraction increases as growth rate increases. At high growth rate, primaryαphase grows as dendrites and contacts more liquid, which contributes to the L +α→γperitectic reaction. During the process,αdendrites are consumed to form fineαgrains.
αphase transforms toα2/γlamellar in subsequent solid phase transformation. In general, the lamellar orientation is perpendicular to growth direction because of the definite orientation betweenαandγphases. Whenαphase nucleates on the cast grains, the lamellar orientation within cast grains is maintained. At high growth rate, there forms manyαgrains whose growth direction deviate from heat flow. When new dendrites nucleate on those grains, the lamellar orientation is maintained. Thus, it is possible to develop“self seeding”technology to control the lamellar orientation.
引文
1 E. A. Loria. Gamma Titaniμm Aluminides as Prospective Structural Materials. Intermetallics. 2000,8:1339 ~1345
2李成功,傅恒志,于翘.航空航天材料.北京:国防工业出版, 2002:16~18
3陈国良,林均品.有序金属间化合物结构材料.北京:冶金工业出版社, 1998:35~38
4 M. Yamaguchi, H. Inui, K. Iito. High-Temperature Structural Intermetallics. ActaMater. 2000, 48:307~322
5黄伯云.钛铝基金属间化合物.长沙:中南工业大学出版社. 1999:288
6张永刚,饰雅芳,陈国良.金属间化合物结构材料.北京:国防工业出版社. 2001:307 ~322
7 T. Noda. Application of Cast Gamma TiAl for Automobiles. Intermetallics. 1998, 6:709~713
8 H. J. Okamoto. Journal of Phase Equilibria. 1993, 14(1):120~128
9 M. Yamaguchi, D. R. Johnson, H. N. Lee,et al. Directional Solidification of TiAl-base Alloys. Intermetallics. 2000, 8:511~517
10 D. R. Johnson, H. Inui, M. Yamaguichi. Crystal Growth of TiAl Alloys. Intermetallics. 1998, 6:647~652
11刘畅,苏彦庆,李新中等. Ti-(44~50)at.%Al合金定向包晶凝固过程中的组织演化.金属学报. 2005:260~266
12刘畅. TiAl二元包晶合金定向凝固组织形成规律研究.哈尔滨工业大学博士论文, 2007
13 B. A. Mueller, R. J. Schaefer, J. H. Perepezko. Undercooling of Aluminum. J. J. Mater. Res. 1987, 2:809
14 D. K. Aswal, M. Shinmura, Y. Hayakawa, M. Kumagawa. In Situ Observation of Melting, Dissolution, Nucleation and Growth of NdBa2Cu3Ox by High Temperature Optical Microscopy. J. Cryst. Growth. 1998, 193:61
15 K. Nagasgio,Y. Takamura, K. Kuribayashi. Coupled Growth in The Peritectic Nd-Ba-Cu-O System from Highly Undercooled Melt. Scripta Mater. 1999, 41:1161
16 C. H .Shin, P. A. Molian, R. W. Mccallom, U. Balachandran. Laser SurfaceRefinement of YBa2Cu3Ox Superconductor. J.Mater.Sci. 1994, 29:1629
17 H. W. Kerr, W. Kurz. Solidification of Peritectic Alloys. International Materials reviews. 1996, 41:129~164
18李双明,吕海燕,李晓历,刘林,傅恒志.包晶合金的定向凝固与生长.稀有金属材料与工程. 2005, 34:234~138
19 Mclean M著,陈石卿,陈荣章译.定向凝固高温材料.航空工业出版社, 1988
20 M. Hillert. Solidification and Casting of Metals. the Metals Society, London. 1979:242
21 D. H. St John, L. M. Hogan. A Simple Prediction of the Rate of the Peritectic Transformation. Acta Metall. 1987, 35:171
22 T. Umeda, T. Okane, W. Kurz, Phase Selection During Solidification of Peritectic Alloys. Acta Mater. 1996, 44:4209
23 O. Hunziker, M. Vandyoussefi, W. Kurz. Phase and Microstructure Selection in Peritectic Alloys Close to the Limit of Consititutional Undercooling. ActaMeter. 1998, 46:6325
24 H. P. Ha, J. D. Hunt. in Sep97, Proceedings of the 4th Int. conf. on Solidification Processing. Ed. J. Beech, H. Jones. Enginneering Materials. University of Sheffield.U.K. 1997:444
25 D. R. Johnson, H. Inui, M. Yamaguchi. Directional solidification and Microstructural of the TiAl-Ti3Al Lamellar Microstructure in Ti-Al-Si Alloys. ActaMater. 1996, 44:2523
26 D. R. Johnson, Y. Masuda, H. Inui,M. Yamaguchi. Alignment of the TiAl-Ti3Al Lamellar Microstructure in TiAl Alloys by Growth From a Seed Material. Acta Mater. 1997, 45:2523~2533
27 D. R. Johnson, Y. Masuda, H. Inui, M. Yamaguchi. Alignment of the TiAl-Ti3Al Lamellar Microstructure in TiAl Alloys by Directional Solidification. Materials Science and Engineering. 1997:577~583.
28 A. K. Singh, D. Banerjee. Transformations inα2+γTitanium Aluminide Alloys Containing Molybdenum: Part I. Solidification Behavior. Metall Mater Trans A. 1997, 28:1735~1743
29 H. N. Lee, D. R. Johnson, H . Inui, M. H. Oh, D. M. Wee, M. Yamaguchi. In: Y. W. Kim, D. M. Dimiduk, M. H. Loretto, editors. Gamma Titaniumaluminides. Warrendale, TMS, 1999:309
30 S. E. Kim, Y. T. Lee, M. H. Oh. H. Inui, M. Yamaguchi. Directional Solidification of TiAl-Si Alloys Using a Polycrystalline Seed. Intermetallics. 2000:399~405
31 T. Yamanaka, D. R. Johnson, H. Inui, M. Yamaguchi. Directional Solidification of TiAl-Re-Si Alloys with Alienedγ/α2 Microstructure. Intermetallics. 1999, 7:779~784
32 M. C. Kim, M. H. Oh, J. H. Lee. et al. Composition and Directionally Solidified TiAl Alloys. Materials Science and Engineering. 1997, A239-240: 570~576
33 H. S. Jung, M. H. Oh, J. H. Lee, D. M. Wee. Microstructure Control of TiAl Alloys ContainingβStabilizers by Directional Solidification. Materials Science and Engineering. 2002, A329–331:13~18
34 K. Biswas,R. Hermann, J. Das,J. Priede, G. Gerbeth, J. Acker. Tailoring the Microstructure and Mechanical Properties of Ti–Al Alloy Using a novel Electromagnetic Stirring method. Scripta Materialia. 2006, 55:1143~1146
35李庆林,沈军,罗文忠等.生长速度对Ti-45at.%Al包晶合金定向凝固组织的影响.材料热处理. 2007, 36(4):14~16
36 P. Busse, F.Meissen. Coupled Growth of The Properitecticα-and the Peritecticγ-Phases in Binary TiTanium Aluminides. Scripta Materialia, 1997 36:653~658
37 Y. C. Liu, Z .Q. Guo, T. Wang. et al. Directional Growth of Metastable Phaseγin Laser-remelted Ti–Al. Journal of Materials Processing Technology. 2001, 108:394~397
38付艳艳,宋月清,惠松晓,米绪军.航空用钛合金的研究与应用进展.稀有金属. 2006, 30(6):851～856
39吕海燕. Cu-Sn包晶合金定向凝固组织研究.西北工业大学博士论文. 2004
40胡汉起.金属凝固原理.机械工业出版社, 1980
41 J. D. Hunt. Solidification and Casting of Metals. London, The Metal Society, 1979:3~12
42 W. Kurz, D. J. Fisher. Dendrite growth at the limit of stability:Tip Radius and Spacing. Acta Metall. 1981, 29:11~20
43 R. Trivedi. Interdendritic Spacing: Part e. A Comparison of Theory and Experiment. Metall Trans A. 1984, 15:977~982
44屈敏,刘林,唐峰涛等.试样直径对Al-Cu合金定向凝固温度梯度和一次枝晶间距的影响.中国有色金属学报. 2008, 18:283
2李成功,傅恒志,于翘.航空航天材料.北京:国防工业出版, 2002:16~18
3陈国良,林均品.有序金属间化合物结构材料.北京:冶金工业出版社, 1998:35~38
4 M. Yamaguchi, H. Inui, K. Iito. High-Temperature Structural Intermetallics. ActaMater. 2000, 48:307~322
5黄伯云.钛铝基金属间化合物.长沙:中南工业大学出版社. 1999:288
6张永刚,饰雅芳,陈国良.金属间化合物结构材料.北京:国防工业出版社. 2001:307 ~322
7 T. Noda. Application of Cast Gamma TiAl for Automobiles. Intermetallics. 1998, 6:709~713
8 H. J. Okamoto. Journal of Phase Equilibria. 1993, 14(1):120~128
9 M. Yamaguchi, D. R. Johnson, H. N. Lee,et al. Directional Solidification of TiAl-base Alloys. Intermetallics. 2000, 8:511~517
10 D. R. Johnson, H. Inui, M. Yamaguichi. Crystal Growth of TiAl Alloys. Intermetallics. 1998, 6:647~652
11刘畅,苏彦庆,李新中等. Ti-(44~50)at.%Al合金定向包晶凝固过程中的组织演化.金属学报. 2005:260~266
12刘畅. TiAl二元包晶合金定向凝固组织形成规律研究.哈尔滨工业大学博士论文, 2007
13 B. A. Mueller, R. J. Schaefer, J. H. Perepezko. Undercooling of Aluminum. J. J. Mater. Res. 1987, 2:809
14 D. K. Aswal, M. Shinmura, Y. Hayakawa, M. Kumagawa. In Situ Observation of Melting, Dissolution, Nucleation and Growth of NdBa2Cu3Ox by High Temperature Optical Microscopy. J. Cryst. Growth. 1998, 193:61
15 K. Nagasgio,Y. Takamura, K. Kuribayashi. Coupled Growth in The Peritectic Nd-Ba-Cu-O System from Highly Undercooled Melt. Scripta Mater. 1999, 41:1161
16 C. H .Shin, P. A. Molian, R. W. Mccallom, U. Balachandran. Laser SurfaceRefinement of YBa2Cu3Ox Superconductor. J.Mater.Sci. 1994, 29:1629
17 H. W. Kerr, W. Kurz. Solidification of Peritectic Alloys. International Materials reviews. 1996, 41:129~164
18李双明,吕海燕,李晓历,刘林,傅恒志.包晶合金的定向凝固与生长.稀有金属材料与工程. 2005, 34:234~138
19 Mclean M著,陈石卿,陈荣章译.定向凝固高温材料.航空工业出版社, 1988
20 M. Hillert. Solidification and Casting of Metals. the Metals Society, London. 1979:242
21 D. H. St John, L. M. Hogan. A Simple Prediction of the Rate of the Peritectic Transformation. Acta Metall. 1987, 35:171
22 T. Umeda, T. Okane, W. Kurz, Phase Selection During Solidification of Peritectic Alloys. Acta Mater. 1996, 44:4209
23 O. Hunziker, M. Vandyoussefi, W. Kurz. Phase and Microstructure Selection in Peritectic Alloys Close to the Limit of Consititutional Undercooling. ActaMeter. 1998, 46:6325
24 H. P. Ha, J. D. Hunt. in Sep97, Proceedings of the 4th Int. conf. on Solidification Processing. Ed. J. Beech, H. Jones. Enginneering Materials. University of Sheffield.U.K. 1997:444
25 D. R. Johnson, H. Inui, M. Yamaguchi. Directional solidification and Microstructural of the TiAl-Ti3Al Lamellar Microstructure in Ti-Al-Si Alloys. ActaMater. 1996, 44:2523
26 D. R. Johnson, Y. Masuda, H. Inui,M. Yamaguchi. Alignment of the TiAl-Ti3Al Lamellar Microstructure in TiAl Alloys by Growth From a Seed Material. Acta Mater. 1997, 45:2523~2533
27 D. R. Johnson, Y. Masuda, H. Inui, M. Yamaguchi. Alignment of the TiAl-Ti3Al Lamellar Microstructure in TiAl Alloys by Directional Solidification. Materials Science and Engineering. 1997:577~583.
28 A. K. Singh, D. Banerjee. Transformations inα2+γTitanium Aluminide Alloys Containing Molybdenum: Part I. Solidification Behavior. Metall Mater Trans A. 1997, 28:1735~1743
29 H. N. Lee, D. R. Johnson, H . Inui, M. H. Oh, D. M. Wee, M. Yamaguchi. In: Y. W. Kim, D. M. Dimiduk, M. H. Loretto, editors. Gamma Titaniumaluminides. Warrendale, TMS, 1999:309
30 S. E. Kim, Y. T. Lee, M. H. Oh. H. Inui, M. Yamaguchi. Directional Solidification of TiAl-Si Alloys Using a Polycrystalline Seed. Intermetallics. 2000:399~405
31 T. Yamanaka, D. R. Johnson, H. Inui, M. Yamaguchi. Directional Solidification of TiAl-Re-Si Alloys with Alienedγ/α2 Microstructure. Intermetallics. 1999, 7:779~784
32 M. C. Kim, M. H. Oh, J. H. Lee. et al. Composition and Directionally Solidified TiAl Alloys. Materials Science and Engineering. 1997, A239-240: 570~576
33 H. S. Jung, M. H. Oh, J. H. Lee, D. M. Wee. Microstructure Control of TiAl Alloys ContainingβStabilizers by Directional Solidification. Materials Science and Engineering. 2002, A329–331:13~18
34 K. Biswas,R. Hermann, J. Das,J. Priede, G. Gerbeth, J. Acker. Tailoring the Microstructure and Mechanical Properties of Ti–Al Alloy Using a novel Electromagnetic Stirring method. Scripta Materialia. 2006, 55:1143~1146
35李庆林,沈军,罗文忠等.生长速度对Ti-45at.%Al包晶合金定向凝固组织的影响.材料热处理. 2007, 36(4):14~16
36 P. Busse, F.Meissen. Coupled Growth of The Properitecticα-and the Peritecticγ-Phases in Binary TiTanium Aluminides. Scripta Materialia, 1997 36:653~658
37 Y. C. Liu, Z .Q. Guo, T. Wang. et al. Directional Growth of Metastable Phaseγin Laser-remelted Ti–Al. Journal of Materials Processing Technology. 2001, 108:394~397
38付艳艳,宋月清,惠松晓,米绪军.航空用钛合金的研究与应用进展.稀有金属. 2006, 30(6):851～856
39吕海燕. Cu-Sn包晶合金定向凝固组织研究.西北工业大学博士论文. 2004
40胡汉起.金属凝固原理.机械工业出版社, 1980
41 J. D. Hunt. Solidification and Casting of Metals. London, The Metal Society, 1979:3~12
42 W. Kurz, D. J. Fisher. Dendrite growth at the limit of stability:Tip Radius and Spacing. Acta Metall. 1981, 29:11~20
43 R. Trivedi. Interdendritic Spacing: Part e. A Comparison of Theory and Experiment. Metall Trans A. 1984, 15:977~982
44屈敏,刘林,唐峰涛等.试样直径对Al-Cu合金定向凝固温度梯度和一次枝晶间距的影响.中国有色金属学报. 2008, 18:283
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