Strength-ductility balance optimization of Fe.sub.2NiCr.sub.0.5Cu.sub.0.2Al.sub.0.3Ti.sub.0.1 multicomponent alloy via doping trace amounts of boron

• Published in: Journal of materials science Vol. 58; no. 16; pp. 7106 - 7118
• Main Authors: Zhang, Guojia, Yan, Hongwei, Zhang, Yongan, He, Tao, Lu, Yiping
• Format: Journal Article
• Language: English
• Published: Springer 01.04.2023
• Subjects: Alloys; Grain boundaries; Specialty metals industry
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-023-08442-2

Precipitation strengthening/hardening technique is known to significantly improve the strength of multicomponent/high-entropy (MCA/HEA) alloys at the expense of their serious embrittlement. Therefore, a proper adjustment of precipitated particles' type, size, and volume fraction is critical to achieve a good strength-plasticity balance. This study proposes a new MCA design approach involving doping trace amounts of boron to strengthen the ductile face-centered cubic (FCC) matrix phase instead of conventional thermomechanical processes to achieve excellent performance. A 90 ppm boron doping in the Fe.sub.2NiCr.sub.0.5Cu.sub.0.2Al.sub.0.3Ti.sub.0.1 MCAs significantly improved their mechanical properties, increasing their yield strength by 33.2% and ultimate tensile strength by 25.1% at relatively high ductility (21.3-25.2%). The addition of trace amounts of boron inhibited the formation and segregation of coarse BCC-based Heusler particles at the grain boundaries while promoting the formation of fine L1.sub.2-type nanoscale precipitates, possessing a coherent relationship with the matrix. These findings are considered instrumental in designing the optimal strategy for enhancing balanced strength/ductility properties of FCC-based MCAs/HEAs with high economic feasibility and a wide range of industrial applications.