Spheroidization behaviour of a Fe-enriched eutectic high-entropy alloy

• 作者: Yu Yin Damon Kent Qiyang Tan Michael Bermingham Ming-Xing Zhang
• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2020,（16）
• 页码范围: 173-179
• 页数: 7页
• 语种: 英文

摘要

A cost-effective Fe-enriched eutectic high-entropy alloy (EHEA),Fe3sNi2sCr25Mo15,was designed and prepared to avoid the use of expensive Co that is commonly used in HEAs.However,the as-cast Fe-enriched EHEA was associated with brittleness.The present work aims to evaluate the possibility and feasibility of spheroidization of the lamellar structure of the EHEA in order to improve the ductility.Due to the high cooling rate of arc-melting,the as-melted Fe35Ni25Cr25Mo15 EHEA was found to be a pseudo eutectic alloy comprised ofalternant σ phase (Cr0.22 Mo0.18Fe0.6-type intermetallic) and face centred cubic(FCC) phase.The lamellar structure in the Fe-enriched EHEA remained stable up to 800 ℃.The instability of the lamellar structure occurred at temperatures over 800 ℃,which was resulted from migration of high-density faults (i.e.lamellar termination and ledges in the lamellae).However,the Fe35Ni2sCr2sMo1s EHEA still exhibited brittleness even after spheroidization at 1100 ℃ for 168 h due to the formation of the hard and brittle σ matrix in the pseudo Fe35Ni25Cr25Mo15 EHEA as a result of decomposition of the lamellar structure.Therefore,in contrast to the softening of traditional eutectic alloys,spheroidization treatment was considered as invalid to improve the ductility of pseudo-eutectic HEA with high fraction of intermetallic phase.The present work provides a valuable reference for those who aim to improve the ductility of brittle EHEA through spheroidization.