Microstructure, grain growth behavior and mechanical properties of W-CoCuFeNi tungsten heavy alloys prepared by infiltration

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Original languageEnglish
Article number105572
Journal / PublicationInternational Journal of Refractory Metals and Hard Materials
Volume98
Online published8 May 2021
Publication statusPublished - Aug 2021

Abstract

W-CoCuFeNi tungsten heavy alloys (WHAs) were fabricated by infiltration at the temperature range of 1440–1560 °C. The microstructure, grain growth behavior and mechanical properties of the WHAs were investigated in this study. The XRD and SEM results showed that the WHAs consisted of rounded W grains distributed in CoCuFeNi high entropy alloy (HEA). In addition, M6W6C (M = Co, Fe)-type η carbides appeared in the interfacial regions of W grains and CoCuFeNi HEA. The W grain size and W—W contiguity were found to increase with increasing sintering temperatures. The activation energy for W grain growth in CoCuFeNi binder matrix was about 367 kJ/mol, which was far higher than that of traditional W-Ni-Fe and W-Ni-Co WHAs. This suggested that W grain coarsening rate in CoCuFeNi HEA was slower than that in traditional binder alloys. For compressive mechanical properties, the yield strength of WHA sintered at 1440 °C reached the highest due to the smallest W grains. The compressive ductility of W-CoCuFeNi sintered at 1560 °C was the worst due to increased W—W contiguity. The bending tests of W-CoCuFeNi WHAs showed that the WHA sintered at 1440 °C also exhibited the highest bending strength. From the fracture morphologies after bending tests, W—W intergranular fracture was the main failure mode for WHAs sintered at 1500 °C and 1560 °C due to increased W—W contiguity.

Research Area(s)

  • Grain growth behavior, High entropy alloy, Mechanical property, Microstructure, Tungsten heavy alloy

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