Experimental study on Nb3Cr2Ti0.9W0.4Fe6 high entropy alloys with high strength and good ductility by laser powder bed fusion

• Published in: Journal of alloys and compounds Vol. 1026; p. 180506
• Main Authors: Gu, Zhen, Li, Jinting, Wang, Jingqi, Lin, Jiahao, Zhang, Shiwei, Fan, Chuanwei, Yuan, Hongjie, Luo, Jun, Xi, Shengqi, Shan, Zhiwei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.05.2025
• Subjects: Laser powder bed fusion; Mechanical property; Microstructure; Nb3Cr2Ti0.9W0.4Fe6; True stress-strain curve; Laser powder bed fusion; Nb3Cr2Ti0.9W0.4Fe6; True stress-strain curve; Microstructure; Mechanical property
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2025.180506

High entropy alloys (HEAs) have been widely used in aerospace complex parts due to their unique mechanical properties. HEAs with body-centered cubic (BCC) structure have high strength and low plasticity. Due to the synergistic effect of solid solution strengthening and lower electron concentration, high entropy alloys containing refractory elements tend to have considerable strength and plasticity. A novel high strength Nb3Cr2Ti0.9W0.4Fe6 HEA was developed in this work. The spherical powders were prepared by the dual process of mechanical alloying and high temperature remelting spheroidization (DP) since such technology has combined effect of mechanical milling (plastic deformation) and temperature lifting (atomic diffusion) to achieve the composition homogenization. At the same time, the powder prepared by gas atomization (GA) method is compared, and the printed parts are compared under the same parameters of laser powder bed fusion (LPBF). The results indicate that DP-SLM has higher microhardness and wear resistance than GA-SLM. The yield strength (YS), ultimate tensile strength (UTS) and average elongation (ε) of the samples measured by DP-SLM were 953 MPa, 1159 MPa and 14.8 %, respectively. The average elongation (ε) is 25 % higher than GA-SLM. The hot compression test of Nb3Cr2Ti0.9W0.4Fe6 was carried out with Gleeble-3800 thermal simulation machine. The thermal processing diagram of the alloy under different stress variables was drawn by establishing the thermal deformation constitutive equation. The DP-SLM material recovers when the deformation temperature is 1000 ℃ with deformation rate stays at 0.01 s−1. Nb3Cr2Ti0.9W0.4Fe6 alloy processed at 1050–1150°C and a strain rate of 0.005∼ 0.1 s−1 shows high power dissipation efficiency (up to 37 %) and better dynamic recrystallization structure. Nb3Cr2Ti0.9W0.4Fe6 can be considered widely used in the engine combustion chamber, guide, turbine blade and turbo disk four hot end components. The BCC-HEA containing refractory element can also realize the synergistic increase of strength and toughness through reasonable design. •A new technique was developed to prepare refractory high entropy alloy powder with uniform composition on the use of additive manuscript.•The yield strength, ultimate tensile strength and average elongation of the samples measured by DP-SLM were 953 MPa, 1159 MPa and 14.8 %, respectively.•When the coefficient is among 0–0.03, the HEA surface will not be subject to plastic deformation.•The average elongation of the DP-SLM (13.4 %) is 25 % higher than that of the GA-SLM (10.7 %).•When the deformation rate is 0.005∼ 0.1 s-1, the power dissipation efficiency of high temperature deformation is higher (up to 37 %).