Laser additive processing effect on microsegregation of 25Cr-35NiBr Fe-based superalloy

ABSTRACT

Two kinds of 25Cr-35NiBr Fe-based superalloy deposits with the distinguishing microsegregation were fabricated through controlling processing parameters of laser additive manufacturing (LAM). The effect of microsegregation on microstructural evolution was investigated thoroughly at high temperature. The results show that the microsegregation of Nb and Ti near cell boundaries plays a dominant role on the microstructural evolution at high temperature. When Nb. and Ti do not segregate significantly near cell boundaries, at elevated temperature the microstructure tends to evolve into a multiscale precipitated phases structure of Cr23C6, Cr7C3 and (Nb, Ti)C to improve the microstructural high-temperature stability. When Nb and Ti are obviously segregated near cell boundaries, at high temperature the microstructure possess a tendency to evolve into a chain (Nb, Ti)C to significantly decline the microstructural high-temperature stability. This research will provide new insights into the performance control and the microstructural evaluation of superalloy fabricated by LAM.

GRAPHICAL ABSTRACT

KEYWORDS:

• Laser additive manufacturing
• 25cr-35NiBr fe-based superalloy
• microsegregation
• microstructural evolution

Highlights

• Microsegregation can be flexibly adjusted by various LAM processes;

• Microsegregation can determine the microstructural evolution paths at high temperature;

• Microsegregation needs to be considered especially for as-fabricated LAMs superalloys.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the Anhui Provincial Key Research and Development Plan [202104a05020023]; Major Science and Technology Projects of China Machinery Industry Group Co., Ltd [SINOMAST-ZDZX-2019-03]; Doctoral Fund Project of Hefei General Machinery Research Institute Co., LTD [2020011740].