Effect of substrate preset temperature on crystal growth and microstructure formation in laser powder deposition of single-crystal superalloy

Liu, Zhaoyang1,2; Wang, Zi3

2018-11

10.1016/j.jmst.2018.04.016

JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY   Impact Factor & Quartile

1005-0302

A successful repair of single-crystal components needs to avoid the stray grain formation and achieves continuous epitaxial growth of columnar dendrites in the repaired zone. In this study, the effect of substrate preset temperature on crystal growth and microstructure formation in laser powder deposition of single-crystal superalloy was studied through an improved mathematical model and corresponding experimental approaches. The results indicated that the variation of substrate preset temperature between -30 degrees C and +210 degrees C changes the molten pool morphology little, but obviously affects the columnar-to-equiaxed transition conditions. The preheating of substrate facilitates the stray grain formation and enlarges the primary columnar dendrite arm spacing, while the situation for precooling of substrate is opposite. Under the specific processing conditions, the critical condition for continuous epitaxial growth is that the substrate preset temperature T-sub >= +90 degrees C. When the substrate preset temperature T-sub is below +90 degrees C, the height ratio of melting depth to total height of the molten pool is larger than that of stray grain, ensuring that stray grains can be completely remelted and the continuous columnar dendrites during the multi-layer laser powder deposition process on (001) surface of single-crystal substrate can be achieved. (C) 2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Single-crystal superalloy Crystal growth Laser powder deposition

SCI ; EI

English

First ; Corresponding

Shenzhen Science and Technology Innovation Commission[JCYJ20170817111811303]

Materials Science ; Metallurgy & Metallurgical Engineering

Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering

WOS:000439396700016

JOURNAL MATER SCI TECHNOL

20181805130442

Crystal growth ; Dendrites (metallography) ; Epitaxial growth ; Grain boundaries ; Single crystals ; Superalloys ; Textures

Metallurgy and Metallography:531 ; Crystalline Solids:933.1 ; Crystal Growth:933.1.2 ; Materials Science:951

MATERIALS SCIENCE

Web of Science

1.Southern Univ Sci & Technol, Coll Innovat & Entrepreneurship, Shenzhen 518055, Peoples R China
2.Southern Univ Sci & Technol, Shenzhen Key Lab Addit Mfg High Performance Mat, Shenzhen 518055, Peoples R China
3.Cent S Univ, State Key Lab Powder Met, Changsha 410083, Hunan, Peoples R China

Liu, Zhaoyang,Wang, Zi. Effect of substrate preset temperature on crystal growth and microstructure formation in laser powder deposition of single-crystal superalloy[J]. JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY,2018,34(11):2116-2124.

Liu, Zhaoyang,&Wang, Zi.(2018).Effect of substrate preset temperature on crystal growth and microstructure formation in laser powder deposition of single-crystal superalloy.JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY,34(11),2116-2124.

Liu, Zhaoyang,et al."Effect of substrate preset temperature on crystal growth and microstructure formation in laser powder deposition of single-crystal superalloy".JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY 34.11(2018):2116-2124.