Effect of Pulse Frequency on the Transport Phenomena and Crystal Growth Behavior in Quasi-Continuous-Wave Laser Powder Deposition of Single-Crystal Superalloy

Liu, Zhaoyang1; Shu, Jiayang2

2020-08-11

10.1007/s11663-020-01937-2

METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE   影响因子和分区

1073-5615

1543-1916

The effect of pulse frequency on the transport phenomena and crystal growth behavior in the quasi-continuous-wave laser powder deposition process of single-crystal superalloy were studied through an improved three-dimensional mathematical model and experiments. Laser powder deposition experiments with single-crystal superalloy were conducted to verify the computational results and analyze the crystal growth behavior. Results showed that the laser mode has a predominant effect on the transport phenomena and the associated crystal growth behavior. The increase of pulse frequency weakens the fluctuation motion of the molten pool and shallows the solidification interface. Under the given processing parameters, the molten pool size decreases quickly with the increase of pulse frequency from 0 to 15 Hz, and then gradually tends to a steady state in the range of 15 to 35 Hz. When the pulse frequency exceeds 35 Hz, the molten pool does not disappear completely during the laser-off period of a pulse cycle. With the increase of pulse frequency from 0 to 35 Hz, the peak temperature of molten pool decreases from 2567.5 K to 2324.7 K, while the peak normal thermal gradient at the solidification interface increases from 2.24 x 10(6)K/m to 1.01 x 10(7)K/m. The fast solidification speed driven by the contraction speed of molten pool during the laser-off period of quasi-continuous-wave laser powder deposition process refines the trunk size of columnar dendrites and facilitates the formation of shrinkage cavities and chainlike carbides. Due to the significant increase of thermal gradient and solidification speed, the quasi-continuous-wave laser powder deposition process of single-crystal superalloy features the columnar dendrites with a better epitaxial growth ability, and acts as an effective method to expand the repair-processing window of single-crystal components.

SUBSTRATE CRYSTALLOGRAPHIC ORIENTATIONS MICROSTRUCTURE DEVELOPMENT NUMERICAL-SIMULATION INCONEL 718 SOLIDIFICATION COLUMNAR NOZZLE ALLOY GRAIN

SCI ; EI

英语

第一 ; 通讯

National Natural Science Foundation of China[91860131][51905253] ; Natural Science Foundation of Guangdong Province of China[2018A030310132] ; Natural Science Foundation of Shenzhen of China[JCYJ20190809152401680]

Materials Science ; Metallurgy & Metallurgical Engineering

Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering

WOS:000558611100001

SPRINGER

20203309051766

Single crystals ; Superalloys ; Carbides ; Thermal gradients ; Dendrites (metallography) ; Deposition ; Transport properties

Metallurgy and Metallography:531 ; Metallography:531.2 ; Thermodynamics:641.1 ; Chemical Operations:802.3 ; Inorganic Compounds:804.2 ; Ceramics:812.1 ; Physical Properties of Gases, Liquids and Solids:931.2 ; Crystalline Solids:933.1 ; Crystal Growth:933.1.2

MATERIALS SCIENCE

Web of Science

1.Southern Univ Sci & Technol, Sch Innovat & Entrepreneurship, Shenzhen 518055, Peoples R China;
2.Southern Univ Sci & Technol, Dept Mech & Energy Engn, Shenzhen Key Lab Addit Mfg High Performance Mat, Shenzhen 518055, Peoples R China

Liu, Zhaoyang,Shu, Jiayang. Effect of Pulse Frequency on the Transport Phenomena and Crystal Growth Behavior in Quasi-Continuous-Wave Laser Powder Deposition of Single-Crystal Superalloy[J]. METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE,2020,51(6):2797-2810.

Liu, Zhaoyang,&Shu, Jiayang.(2020).Effect of Pulse Frequency on the Transport Phenomena and Crystal Growth Behavior in Quasi-Continuous-Wave Laser Powder Deposition of Single-Crystal Superalloy.METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE,51(6),2797-2810.

Liu, Zhaoyang,et al."Effect of Pulse Frequency on the Transport Phenomena and Crystal Growth Behavior in Quasi-Continuous-Wave Laser Powder Deposition of Single-Crystal Superalloy".METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE 51.6(2020):2797-2810.