Microstructures and Tensile Mechanical Properties of Consolidated Copper

Liang, Chong; Ma, Minglin; Zhang, Deliang

doi:10.1590/1516-1439.027715

Cited by 5 publications

(1 citation statement)

References 17 publications

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“…According to the EBSD results in Figure 8 a,b, the misorientations of the grain boundaries show a significant difference with the change of elements, although the Ta 0.4 alloy has similar macro-mechanical properties and nanohardness than the Nb 0.4 alloy. The DefRex diagram from EBSD shows the crystallization status, which reflects the existence of dislocations to a certain extent [ 41 ], as shown in Figure 8 c. Deformed grains (marked as red) indicate that the interior is full of dislocations; the formation of the substructure (yellow) needs to consume and absorb some dislocations, and there is basically no dislocation formation inside the recrystallized (blue). The blue text in Figure 8 (c1) indicates that the FCC phase occupies 100% of the CoCrFeNi alloy, and the recrystallization ratio reaches 91.3% in the FCC phase.…”

Section: Discussionmentioning

confidence: 99%

Strengthening Mechanisms in CoCrFeNiX0.4 (Al, Nb, Ta) High Entropy Alloys Fabricated by Powder Plasma Arc Additive Manufacturing

et al. 2021

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In high entropy alloys (HEAs), the addition of large-size atoms results in lattice distortion and further leads to solid solution strengthening or precipitation strengthening. However, the relationship between atomic radius, solid solution strengthening and precipitation strengthening has not been discerned yet. In this work, CoCrFeNiX0.4 (X = Al, Nb, Ta, with an equi-atomic radius) HEAs were prepared by powder plasma arc additive manufacturing (PPA-AM) and evaluated for their mechanical properties. Compression and nano-indentation hardness tests showed that the HEA with Ta showed the best properties. The influence of atomic radius and solid solubility on solid solution strengthening was investigated and the main strengthening mechanism that determines the mechanical properties of the developed HEAs was analyzed. The results showed that (i) the CoCrFeNiAl0.4 alloy did not show any solid solution strengthening effect and that a clear relation between solid solution strengthening and atomic size was not observed; (ii) in both CoCrFeNiTa0.4 and CoCrFeNiNb0.4 HEAs, precipitation strengthening and grain boundary strengthening effects are observed, wherein the difference in mechanical properties between both the alloys can be mainly attributed to the formation of fine eutectic structure in CoCrFeNiTa0.4; and (iii) from the microstructural analyses, it was identified that, in the CoCrFeNiTa0.4 HEA, the location containing a fine eutectic structure is accompanied by the formation of low-angle grain boundaries (LAGBs), which is also the region where deformed grains gather, giving rise to improved mechanical strengthening.

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Section: Discussionmentioning

confidence: 99%