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Influence of pulsed direct current on the growth rate of intermetallic phases in the Ni–Al system during reactive spark plasma sintering

Abedi, M ; Sharif University of Technology | 2022

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  1. Type of Document: Article
  2. DOI: 10.1016/j.scriptamat.2022.114759
  3. Publisher: Acta Materialia Inc , 2022
  4. Abstract:
  5. The effect of pulsed direct current (PDC) on solid-state diffusion in the Ni–Al binary system was investigated. Two experimental schemes were employed: in the presence and absence of an electric field. The diffusion couples were heat-treated for 1.5, 3, and 5 h at 803, 833, and 863 K. Under the investigated conditions, only two intermetallic phases (NiAl3 and Ni2Al3) formed at the boundary of the metals. It was shown that the PDC passing through the diffusion couple significantly enhanced the growth rates of both phases. The apparent reaction–diffusion coefficients were DNiAl3=4.0×10−9exp(−[Formula presented]) and DNi2Al3=9.7×10−9exp(−[Formula presented]) in the field-assisted scheme, whereas their corresponding values in the field-insulated scheme were DNiAl3=6.1×10−5exp(−[Formula presented]) and DNi2Al3=3.7×10−4exp(−[Formula presented]). The results directly imply that the effective activation energy of diffusion decreases by approximately two times when the PDC passes through the media. © 2022 Acta Materialia Inc
  6. Keywords:
  7. Activation energy ; Diffusion ; Aluminum alloys ; Binary alloys ; Diffusion in solids ; Electric fields ; Growth rate ; Intermetallics ; Nickel ; Nickel compounds ; Binary systems ; Condition ; Diffusion couple ; Experimental scheme ; Intermetallic-phases ; Nickel aluminides ; Pulsed direct current ; Reactive spark plasma sintering ; Solid-state diffusion ; Spark-plasma-sintering ; Spark plasma sintering
  8. Source: Scripta Materialia ; Volume 216 , 2022 ; 13596462 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S135964622200255X