Microstructure and mechanical properties of WMoTaNbTi refractory high-entropy alloys fabricated by selective electron beam melting. (10th May 2022)

• Record Type: Journal Article
• Authors: Xiao, Bang; Jia, Wenpeng; Tang, Huiping; Wang, Jian; Zhou, Lian
• Is Part Of: Journal of materials science & technology. Volume 108(2022)
• Page Start: 54
• Page End: 63
• Publication Date: 2022-05-10
• Subjects: Refractory high-entropy alloys -- Selective electron beam melting -- Solidification cracking -- Porosity -- Solid-solution strengthening; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2021.07.041
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: WMoTaNbTi RHEAs are first manufactured using selective electron beam melting. WMoTaNbTi RHEAs fabricated at a scanning rate of 2.5 m/s are completely fused without lack of fusion regions. Ti could bridge the cracks formed at the solidification stage. WMoTaNbTi RHEAs own better ductility than WMoTaNb fabricated by vacuum arc melting in previous works. Abstract: WMoTaNbTi RHEAs formed by SEBM with negative defocus distance were investigated. Four scanning speeds were applied, an electron beam with scanning speed at 2.5 m/s completely fused the premixed WMoTaNb alloyed powder and pure Ti powder. Significant vaporization of Nb and Ti elements happened during the formation of WMoTaNbTi RHEAs, however, the single BCC phase remains stable. Weakened solid-solute strengthening caused by elemental vaporization, dropping percentage of Nb and Ti solutes in the matrix as well as improved ductilizing effects with decreasing scanning speeds leads to falling microhardness and better local ductility. Microhardness of scanning speed at 4.0 m/s, 3.5 m/s, 3.0 m/s and 2.5 m/s is 578 ± 17 HV, 576 ± 12 HV, 573 ± 10 HV and 511 ± 2 HV, respectively. The as-deposited WMoTaNbTi RHEA formed at a scanning speed of 2.5 m/s displays ultimate strength of 1312 MPa. Graphical abstract: Image, graphical abstract