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Microstructure and Mechanical Properties of New AlCo x CrFeMo 0.5 Ni High‐Entropy Alloys
Author(s) -
Hsu ChinYou,
Wang WoeiRen,
Tang WeiYeh,
Chen SweKai,
Yeh JienWei
Publication year - 2010
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.200900171
Subject(s) - alloy , materials science , microstructure , superalloy , metallurgy , high entropy alloys , cobalt , thermodynamics , phase (matter) , dendrite (mathematics) , chemistry , physics , geometry , mathematics , organic chemistry
Abstract Effects of Co content on microstructures and hot hardness of a new high‐entropy alloy system, AlCo x CrFeMo 0.5 Ni ( x = 0.5 to 2.0) were investigated. As cobalt content increases, the microstructure changes from dendrite to polygrain type and the constituent phases change from BCC + σ at x = 0.5 to BCC + FCC + σ at x = 2.0. The alloy hardness varies from Hv 788 at x = 0.5 to Hv 596 at x = 2.0. This can be explained with the relative amount of hard σ phase, medium hard BCC phase and soft FCC phase. All the AlCo x CrFeMo 0.5 Ni alloys possess higher hardness level than that of Ni‐based superalloys In 718/In 718 H from room temperature to 1273 K. They obey the Westbrook equation presenting the normal heating behavior. Both alloys of x = 0.5 and 1.0 exhibit a transition temperature higher than that of Co‐based alloy T‐800 by about 200 K. They also have a high hot hardness of Hv 347 at 1273 K, which is higher than those of In 718 and In718 H by Hv 220. The strengthening mechanism for their superiority is proposed. The AlCo x CrFeMo 0.5 Ni alloy system has great potential in high‐temperature applications.