.png){kind=icon}
.png){kind=icon}
Return
On the creep behaviour of a hetero-structured and L12-strengthened medium-entropy alloy
.png){kind=icon}
OA
AI
Z
C
DOI：10.1080/17452759.2026.2684886.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Recently, some L12-strengthened or hetero-structured high/medium-entropy alloys (HEAs/MEAs) which possess extraordinary strength-ductility synergy at both ambient and high temperatures have been developed, demonstrating fascinating potential for critical applications under extreme conditions. However, reports on creep behaviour of these alloys are lacking. Here, we create a heterogeneous microstructure in a precipitation-strengthened MEA, (CoCrNi)94(TiAl)6, by additive manufacturing and aging treatment and investigate its tensile and creep properties. The heterogeneous microstructure consists of recrystallized grains with large lamellar γ′ precipitates and un-recrystallized grains with numerous ultrafine spherical γ′, which induces high heterogeneous deformation induced stresses during deformation at ambient and elevated temperatures leading to excellent tensile strengths. Moreover, the alloy presents an extraordinary creep life (∼750 h) and ultralow strain rates (∼10−7/s) in the steady-state creep stage at 200 MPa/650 °C. Owing to the precipitate size difference in the un-recrystallized and recrystallized regions, the former deforms mainly by dislocation slip during creep while the latter deforms through multiple mechanisms, i.e. dislocation slip + formation of stacking faults + twinning. With increased temperature, the deformation becomes increasingly planar. However, neither superlattice stacking faults nor twins are associated with micro-segregation, indicating that the creep deformation is not dictated by diffusion-controlled solute redistribution.
Keywords:
High/medium-entropy alloys
selective laser melting
heterogeneous microstructure
creep properties
deformation mechanism
Journal
IF:
8.8
Papers:
1.0K
Citations:
4.9K
Organization
Cited Papers