TY - JOUR
T1 - Control of microstructure and mechanical properties of laser solid formed Inconel 718 superalloy by electromagnetic stirring
AU - Liu, Fencheng
AU - Cheng, Hongmao
AU - Yu, Xiaobin
AU - Yang, Guang
AU - Huang, Chunping
AU - Lin, Xin
AU - Chen, Jing
N1 - Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2018/2/1
Y1 - 2018/2/1
N2 - The coarse columnar grains and special interface in laser solid formed (LSFed) Inconel 718 superalloy workpieces seriously affect their mechanical properties. To improve the microstructure and mechanical properties of LSFed Inconel 718 superalloy, electromagnetic stirring (EMS) was introduced to alter the solidification process of the molten pool during LSF. The results show that EMS could not completely eliminate the epitaxially growing columnar grains, however, the strong convection of liquid metals can effectively influence the solid–liquid interface growing mode. The segregation of alloying elements on the front of solid–liquid interface is inhibited and the degree of constitutional supercooling decreases correspondingly. Comparing the microstructures of samples formed under different process parameters, the size and amount of the γ+Laves eutectic phases formed in interdendritic area decrease along with the increasing magnetic field intensity, resulting in more uniformly distributed alloying elements. The residual stress distribution is proved to be more uniform, which is beneficial to the grain refinement after recrystallilzaiton. Mechanical properties testing results show an improvement of 100 MPa in tensile strength and 22% in elongation was obtained after EMS was used. The high cycle fatigue properties at room temperature was also improved from 4.09 × 104 cycles to 8.21 × 104 cycles for the as-deposited samples, and from 5.45 × 104 cycles to 12.73 × 104 cycles for the heat treated samples respectively.
AB - The coarse columnar grains and special interface in laser solid formed (LSFed) Inconel 718 superalloy workpieces seriously affect their mechanical properties. To improve the microstructure and mechanical properties of LSFed Inconel 718 superalloy, electromagnetic stirring (EMS) was introduced to alter the solidification process of the molten pool during LSF. The results show that EMS could not completely eliminate the epitaxially growing columnar grains, however, the strong convection of liquid metals can effectively influence the solid–liquid interface growing mode. The segregation of alloying elements on the front of solid–liquid interface is inhibited and the degree of constitutional supercooling decreases correspondingly. Comparing the microstructures of samples formed under different process parameters, the size and amount of the γ+Laves eutectic phases formed in interdendritic area decrease along with the increasing magnetic field intensity, resulting in more uniformly distributed alloying elements. The residual stress distribution is proved to be more uniform, which is beneficial to the grain refinement after recrystallilzaiton. Mechanical properties testing results show an improvement of 100 MPa in tensile strength and 22% in elongation was obtained after EMS was used. The high cycle fatigue properties at room temperature was also improved from 4.09 × 104 cycles to 8.21 × 104 cycles for the as-deposited samples, and from 5.45 × 104 cycles to 12.73 × 104 cycles for the heat treated samples respectively.
KW - Electromagnetic stirring
KW - Laser solid forming
KW - Microstructure control
KW - Superalloy
UR - http://www.scopus.com/inward/record.url?scp=85029695404&partnerID=8YFLogxK
U2 - 10.1016/j.optlastec.2017.09.022
DO - 10.1016/j.optlastec.2017.09.022
M3 - 文章
AN - SCOPUS:85029695404
SN - 0030-3992
VL - 99
SP - 342
EP - 350
JO - Optics and Laser Technology
JF - Optics and Laser Technology
ER -