Fine Structure in Multi-Phase Zr8Ni21-Zr7Ni10-Zr2Ni7 Alloy Revealed by Transmission Electron Microscope

Materials

Haoting Shen¹  Leonid A. Bendersky²  Kwo Young¹  Jean Nei¹ 

[1] BASF-Ovonic, 2983 Waterview Drive, Rochester Hills, MI 48309, USA; E-Mails:;Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; E-Mail:

关键词: intermetallics;    nanocrystalline structure;    microstructure;    planar faults;    scanning electron microscopy;    transmission electron microscopy;   

DOI  :  10.3390/ma8074618

来源: mdpi

【 摘 要 】

The microstructure of an annealed alloy with a Zr₈Ni₂₁ composition was studied by both scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The presence of three phases, Zr₈Ni₂₁, Zr₂Ni₇, and Zr₇Ni₁₀, was confirmed by SEM/X-ray energy dispersive spectroscopy compositional mapping and TEM electron diffraction. Distribution of the phases and their morphology can be linked to a multi-phase structure formed by a sequence of reactions: (1) L → Zr₂Ni₇ + L’; (2) peritectic Zr₂Ni₇ + L’ → Zr₂Ni₇ + Zr₈Ni₂₁ + L”; (3) eutectic L” → Zr₈Ni₂₁ + Zr₇Ni₁₀. The effect of annealing at 960 °C, which was intended to convert a cast structure into a single-phase Zr₈Ni₂₁ structure, was only moderate and the resulting alloy was still multi-phased. TEM and crystallographic analysis of the Zr₂Ni₇ phase show a high density of planar (001) defects that were explained as low-energy boundaries between rotational variants and stacking faults. The crystallographic features arise from the pseudo-hexagonal structure of Zr₂Ni₇. This highly defective Zr₂Ni₇ phase was identified as the source of the broad X-ray diffraction peaks at around 38.4° and 44.6° when a Cu-K was used as the radiation source.

【 授权许可】

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