冷却速率对β 凝固γ-TiAl合金硼化物和室温拉伸性能的影响
Effect of Cooling Rate on Boride and Room Temperature Tensile Properties of β-Solidifying γ-TiAl Alloys
查看参考文献29篇
|
文摘
|
设计了不同厚度台阶铸板以实现冷却速率梯度,采用离心熔模铸造制备了不同冷却速率的β凝固含B γ-TiAl合金样品,研究了冷却速率对硼化物和室温拉伸性能的影响。结果表明,硼化物分布在晶界,其长径比随冷却速率的提高而增大,而形貌由短棒状转变为丝带状。慢冷样品中短棒状TiB为B27结构,而快冷样品中丝带状TiB为Bf结构。2种结构TiB均存在生长各向异性,[010]和[100]分别为Bf和B27结构的最慢生长方向,前者更为显著,这可能与上述方向Ti、B原子周期性间隔排列,原子短程重排更为困难有关。随着冷却速率提高,材料屈服强度提高,但室温塑性下降,这与快冷样品中的细长丝带状硼化物容易萌生裂纹并迅速扩展有关;慢冷样品中的短棒状硼化物不易萌生裂纹,相应室温塑性较好。 |
|
其他语种文摘
|
β -solidifying γ-TiAl alloys have attracted much attention for their higher specific strength and better mechanical properties at elevated temperature. They usually need some boron addition to refine the lamellar grain size, which is believed to improve their poor room temperature ductility. However, the boron addition may cause some side effects on mechanical properties for the formation of borides with unfavorable morphology and crystal structure, which is severely influenced by the alloy composition and cooling rate during casting. The components of γ-TiAl applied usually have complex structure, such as different thicknesses, which leads to different cooling rates and therefore different microstructures and mechanical properties. To evaluate the influence of cooling rate on the microstructure and mechanical properties of γ-TiAl investment casting, plate with step thicknesses was designed to achieve different cooling rates. Step plates of β-solidifying boron-containing TiAl alloy were fabricated by centrifugal casting in Y_2O_3 facing coating ceramic moulds. It was found that boride mainly distributed on grain boundary, and its aspect ratio increased with increasing cooling rate, with its morphology varying from short, flat plate to long, curvy ribbon. The short plate and curvy ribbon borides were TiB with B27 and Bf structure, respectively. Both types of boride exhibit anisotropic growth characteristics (especially for Bf structure), with the slowest growth rate along [100] and [010] for B27 structure and Bf structure, respectively. This is attributed to the difficulty of atomic rearrangement along corresponding directions during solidification. The cooling rate increase caused the increase of yield strength but the decrease of room temperature ductility, the former results from the decreasing of grain size and lamellar spacing, while the latter results from the easy cracking nucleation and propagation of the long curvy boride, leaving smooth curvy surfaces on the fracture surface. Samples containing short flat plate boride showed better ductility, and no smooth curvy surface was observed. |
|
来源
|
金属学报
,2020,56(2):203-211 【核心库】
|
|
DOI
|
10.11900/0412.1961.2019.00100
|
|
关键词
|
γ-TiAl 合金
;
β凝固
;
熔模铸造
;
冷却速率
;
硼化物
;
拉伸性能
|
|
地址
|
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
3.
三峡大学机械与动力学院, 宜昌, 443002
|
|
语种
|
中文 |
|
文献类型
|
研究性论文 |
|
ISSN
|
0412-1961 |
|
学科
|
金属学与金属工艺 |
|
基金
|
国家自然科学基金
;
国家重点研发计划项目
|
|
文献收藏号
|
CSCD:6664991
|
参考文献 共
29
共2页
|
|
1.
杨锐. 钛铝金属间化合物的进展与挑战.
金属学报,2015,51:129
|
CSCD被引
84
次
|
|
|
|
|
2.
Kim Y W. Progress in the understanding of gamma titanium aluminides.
JOM,1991,43(8):40
|
CSCD被引
83
次
|
|
|
|
|
3.
Kim Y W. Ordered intermetallic alloys, part III: Gamma titanium aluminides.
JOM,1994,46(7):30
|
CSCD被引
148
次
|
|
|
|
|
4.
Hu D W. Role of boron in TiAl alloy development: a review.
Rare Met,2016,35:1
|
CSCD被引
14
次
|
|
|
|
|
5.
Larsen D E. Effect of XD™TiB2 volume fraction on the microstructure of a cast near-gamma titanium aluminide alloy.
MRS Proc,1990,194:285
|
CSCD被引
1
次
|
|
|
|
|
6.
Cheng T T. The mechanism of grain refinement in TiAl alloys by boron addition-An alternative hypothesis.
Intermetallics,2000,8:29
|
CSCD被引
44
次
|
|
|
|
|
7.
Inkson B J. Boride morphology in a (Fe, V, B)Ti-alloy containing B2-phase.
Acta Metall. Mater,1995,43:1429
|
CSCD被引
3
次
|
|
|
|
|
8.
Godfrey A B.
Grain refinement of a gamma-based titanium aluminide using microalloy additions,1996
|
CSCD被引
2
次
|
|
|
|
|
9.
Hecht U. Grain refinement by low boron additions in niobium-rich TiAl-based alloys.
Intermetallics,2008,16:969
|
CSCD被引
31
次
|
|
|
|
|
10.
De Graef M. The evolution of metastable Bf borides in a Ti-Al-B alloy.
Acta Metall. Mater,1992,40:3395
|
CSCD被引
6
次
|
|
|
|
|
11.
Hu D. Effect of composition on grain refinement in TiAl-based alloys.
Intermetallics,2001,9:1037
|
CSCD被引
32
次
|
|
|
|
|
12.
Kitkamthorn U. The structure of ribbon borides in a Ti-44Al-4Nb-4Zr-1B alloy.
Intermetallics,2006,14:759
|
CSCD被引
6
次
|
|
|
|
|
13.
Hyman M E. Evolution of boride morphologies in TiAl-B alloys.
Metall. Mater. Trans. A,1991,22:1647
|
CSCD被引
27
次
|
|
|
|
|
14.
杨莉莉. 抽拉速率对定向凝固Ti-47Al-2Cr-2Nb-0.8B合金组织的影响.
金属学报,2010,46:879
|
CSCD被引
4
次
|
|
|
|
|
15.
Imayev R M. Alloy design concepts for refined gamma titanium aluminide based alloys.
Intermetallics,2007,15:451
|
CSCD被引
61
次
|
|
|
|
|
16.
Hu D. Microstructure and tensile properties of investment cast Ti-46Al-8Nb-1B alloy.
Scr. Mater,2002,47:273
|
CSCD被引
9
次
|
|
|
|
|
17.
Hu D. Effect of boron addition on tensile ductility in lamellar TiAl alloys.
Intermetallics,2002,10:851
|
CSCD被引
39
次
|
|
|
|
|
18.
Lin B C. Effect of surface topography on room temperature tensile ductility of TiAl.
JOM,2017,69:2583
|
CSCD被引
2
次
|
|
|
|
|
19.
林博超.
表面状态和铸造缺陷对TiAl力学性能影响研究,2017
|
CSCD被引
1
次
|
|
|
|
|
20.
刘仁慈.
Ti-47Al-2Cr-2Nb-0.15B合金挤压变形组织演变及其力学性能研究,2013
|
CSCD被引
2
次
|
|
|
|
|
了解气象卫星更多信息，请访问