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Title: Solid state amorphization of metastable Al 0.5TiZrPdCuNi high entropy alloy investigated by high voltage electron microscopy

Here, the phase stability of high entropy alloy (HEA), Al 0.5TiZrPdCuNi, under fast electron irradiation was studied by in-situ high voltage electron microscopy (HVEM). The initial phase of this alloy quenched from the melt was dependent on cooling rate. At high cooling rates an amorphous phase was obtained, whereas a body-centered cubic ( b.c.c.) phase were obtained at low cooling rates. By thermal crystallization of the amorphous phase b.c.c. phase nano-crystals were formed. Upon fast electron irradiation solid state amorphization (SSA) was observed in b.c.c. phase regardless of the initial microstructure (i.e., “coarse crystalline structure” or “nano-crystalline structure with grain boundaries as a sink for point defects”). SSA behavior in the Al 0.5TiZrPdCuNi HEAs was investigated by in-situ transmission electron microscopy observations. Because the amorphization is very rarely achieved in a solid solution phase under fast electron irradiation in common metallic materials, this result suggests that the Al 0.5TiZrPdCuNi HEA from other common alloys and the other HEAs. The differences in phase stability against the irradiation between the Al 0.5TiZrPdCuNi HEA and the other HEAs were discussed. This is the first experimental evidence of SSA in HEAs stimulated by fast electron irradiation.
Authors:
 [1] ;  [2] ;  [2] ;  [3]
  1. Osaka Univ., Osaka (Japan)
  2. Tohoku Univ., Sendai (Japan)
  3. Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Materials Chemistry and Physics
Additional Journal Information:
Journal Volume: 210; Journal Issue: C; Journal ID: ISSN 0254-0584
Publisher:
Elsevier
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; High entropy alloys; In situ observation; High voltage electron microscopy; Solid state amorphization; Phase transformation
OSTI Identifier:
1454411