TY - JOUR
T1 - A Direct Observation of Ordered Structures Induced by Cu Segregation at Grain Boundaries of Al 7075 Alloys
AU - Parajuli, Prakash
AU - Mendoza-Cruz, Rubén
AU - Hurtado-Macias, Abel
AU - Santiago, Ulises
AU - Yacamán, Miguel José
N1 - Funding Information:
The authors are thankful to the Welch Foundation for the support provided through Grant No. AX-1615, to the Kleberg Advanced Material Characterization Centre (KAMC2), University of Texas at San Antonio, USA, for the electron microscopy facility, and to the National Council for Science and Technology (Conacyt), Mexico, for the support provided through the Postdoctoral Scholarship Program.
Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2018/10/10
Y1 - 2018/10/10
N2 - The experimental investigation of the atomic-scale structure and chemistry of the grain boundaries by resolving the sites and chemical identities of the atoms comprising the interface is crucial to understand the implication of preferential atomic segregation at grain boundaries. Here, the authors report the ordered-structures induced by substitutional Cu segregation at the Al alloy 7075 coincidence site lattice grain boundaries, namely, ∑13b and ∑7, using Cs-aberration corrected scanning transmission electron microscopy. Unlike the single-atom interstitial hollow site segregation behavior at the boundary region (predicted in the theoretical studies and considered on analysis of segregation effects), the authors demonstrate segregation of Cu atoms on two columns opposite to each other across the interface forming an ordered parallel array of segregating atoms in substitutional core sites. This is the first time that this type of parallel array segregation behavior is reported. Furthermore, based on intensity profiles and scanning transmission electron microscopy Z-contrast principle, non-uniformly (high and low) segregated mixed atomic columns are predicted at the grain boundaries.
AB - The experimental investigation of the atomic-scale structure and chemistry of the grain boundaries by resolving the sites and chemical identities of the atoms comprising the interface is crucial to understand the implication of preferential atomic segregation at grain boundaries. Here, the authors report the ordered-structures induced by substitutional Cu segregation at the Al alloy 7075 coincidence site lattice grain boundaries, namely, ∑13b and ∑7, using Cs-aberration corrected scanning transmission electron microscopy. Unlike the single-atom interstitial hollow site segregation behavior at the boundary region (predicted in the theoretical studies and considered on analysis of segregation effects), the authors demonstrate segregation of Cu atoms on two columns opposite to each other across the interface forming an ordered parallel array of segregating atoms in substitutional core sites. This is the first time that this type of parallel array segregation behavior is reported. Furthermore, based on intensity profiles and scanning transmission electron microscopy Z-contrast principle, non-uniformly (high and low) segregated mixed atomic columns are predicted at the grain boundaries.
KW - Al alloys
KW - Cu adsorbate
KW - Z-contrast
KW - grain boundaries
KW - segregation
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U2 - 10.1002/pssa.201800240
DO - 10.1002/pssa.201800240
M3 - Article
AN - SCOPUS:85054823111
SN - 1862-6300
VL - 215
JO - Physica Status Solidi (A) Applications and Materials Science
JF - Physica Status Solidi (A) Applications and Materials Science
IS - 19
M1 - 1800240
ER -