Phase transformation - induced strengthening of an additively manufactured multi- principal element CrMnFeCoNi alloy

Abstract

A laser metal deposition (LMD) process has been applied to the fabrications of the (CrMnFeCoNi)1-xFex (x = 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) Multi-principal elements alloys (MPEAs). It is found that the LMD-fabricated (CrMnFeCoNi)50Fe50 alloy keeps a single-phase solid solution microstructure. Compared with the CrMnFeCoNi MPEA, the (CrMnFeCoNi)50Fe50 alloy obtains remarkably improved plasticity from 45% to 77%, while maintaining tensile strength (415 MPa to 470 MPa), due to the strain-induced FCC to BCC phase transformation. Furthermore, the (CrMnFeCoNi)50Fe50 alloy shows excellent mechanical properties at cryogenic temperatures. This alloy has lower cost and better mechanical property than the well-known CrMnFeCoNi MPEA by the addition of inexpensive Fe elements. The present work provides important pathways in the development of low-cost LMD-fabricated MPEA for cryogenic engineering applications.

Keywords

• Multi-principal element alloy
• Laser metal deposition
• Microstructure
• Transformation-induced plasticity