Solidification Characteristics and Microstructure Evolution of Rapidly Solidified Cu Alloys

Abstract

Cu60Ni40 alloy was taken as the research object. The alloy was undercooled by fluxing method and circulation superheating method, and the solidified samples with different undercoolings were obtained by natural cooling method. The solidification process of undercooled melt was photographed by high-speed camera, and the transformation of solidification front morphology was studied. The microstructure and morphology of all undercooled samples were analyzed. It is found that the microstructure and morphology of Cu60Ni40 alloy change through the evolution process of “coarse dendrite-equiaxed crystal-oriented fine dendrite-equiaxed crystal” with the undercooling. Finally, the electron backscatter diffraction characterization of 261 K grain refinement structure shows that recrystallization occurs in the grain refinement structure with high undercooling, such as high proportion of high angle grain boundaries, random orientation of equiaxed grains and a large number of annealing twins found in the microstructure.

Keywords

undercooling / solidification front / microstructure / recrystallization

References

[1] Wei B, Yang C, Zhou Y. High Undercooling and Rapid Solidification of Ni-32.5%Sn Eutectic Alloy[J]. Acta Metallurgica Et Materialia, 1991, 39(6): 1 249-1 258.

[2] Wang P, Liu F, Lu Y, Yang C, Yang G, Zhou Y. Grain Refinement and Coarsening in Hypercooled Solidi Fication of Eutectic Alloy[J]. Journal of Crystal Growth, 2008, 310(19): 4 309-4 313.

[3] Zheng H, Yu Y, Li J. Microstructural Evolution of Undercooled Ni-40wt%Pb Hypermonotectic Alloy[J]. Materials Science Forum, 2005, 475: 2 651-2 654.

[4] Dragnevski Kalin I, Mullis Andrew M, Cochrane Robert F. The Effect of Experimental Variables on the Levels of Melt Undercooling[J]. Materials Science and Engineering A, 2004, 375–377: 485-487.

[5] Eckler K, Grtner F, Assadi H. Phase Selection, Growth, and Interface Kinetics in Undercooled Fe-Ni Melt Droplets[J]. Materials Science and Engineering A, 1997, 226(1): 410-414.

[6] Perepezko JH. Nucleation Reactions in Undercooled Liquids[J]. Materials Science and Engineering A, 1984, 178(1): 105-111.

[7] Yang C, Liu F, Yang G, Zhou Y. Structure Evolution Upon Non-equilibrium Solidification of Bulk Undercooled Fe-B system[J]. Journal of Crystal Growth, 2009, 311(2): 404-412.

[8] Zhou J, Li J. Effect of Denucleating Glass Composition on Undercooling of Fe83Ga17 Alloy Melts[J]. Journal of Alloys and Compounds, 2009, 467(1–2): 179-181.

[9] Kattamis TZ. Mechanism of Establishment of Cast Microstructure during Solidification of Highly Undercooled Melts[J]. Journal of Crystal Growth, 1976, 34(2): 215-220.

[10] Jones BL, Weston GM. Grain Refinement in Undercooled Copper[J]. Journal of the Australasian. Institute of Metal, 1970, 15: 3 167.

[11] Xi Z, Yang G, Zhou Y. Growth Morphology of Ni-3Si in High Undercooled Ni-Si Eutectic Alloy[J]. Progress in Natural Science, 1997, 5: 114-121.

[12] Cochrane RF, Battersby S, Mullis AM. The Mechanisms for Spontaneous Grain Refinement in Undercooled Cu-O and Cu-Sn Melts[J]. Materials Science and Engineering A, 2001, 304: 262-266.

[13] Li J, Lv Y, Yang G, Zhou Y. Directional Solidification of Undercooled Melt[J]. Progress in Natural Science, 1997, 7(6): 736-741.

[14] Liu F, Yang G. Rapid Solidification of Highly Undercooled Bulk Liquid Superalloy: Recent Developments, Future Directions[J]. International Metallurgical Reviews, 2006, 51(3): 145-170.

[15] Mariano NA, Souza C, Oliveira M, Kuri SE. Enhanced Corrosion Resistance of Amorphous and Nanocrystalline FeNbB Alloys[J]. Materials Science Forum, 2000, 343–346: 861-866.

[16] Jie W. Progress of Solidification Researches and the Applications in Materials Processing[J]. Journal of Materials Science and Technology, 2001, 5: 575-576.

[17] Chen Z, Yang Y, Chen Q, Xu J, Tang Y, Liu F. Recalescence Effect Simulation and Microstructure Evolution of Undercooled Fe82B17Si1 Alloy[J]. Acta Metallurgica Sinica, 2014, 50(7): 795-801.

[18] Ma K, Zhao Y, Xu X, Hou H. The Effect of Undercooling on Growth Velocity and Microstructure of Ni95Cu5 Alloys[J]. Journal of Crystal Growth, 2019, 513: 30-37.

[19] Liu F, Yang G. Rapid Solidification of Highly Undercooled Bulk Liquid Superalloy: Recent Developments, Future Directions[J]. International Materials Reviews, 2013, 51(3): 145-170.

[20] Boettinger WJ, Coriell SR, Trivedi R. Rapid Solidification Processing: Principles and Technologies IV[M], 1988 Baton Rouge: Claitor’s Pulishing Division.