Effect of hierarchical multimodal microstructure evolution on tensile properties and fracture toughness of rapidly solidified Mg–Zn–Y–Al alloys with LPSO phase

Nishimoto, Sei‐ichi; Koguchi, Yuta; Yamasaki, Michiaki; Kawamura, Y.

doi:10.1016/j.msea.2021.142348

Cited by 17 publications

(4 citation statements)

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“…At the crack tip, which is subjected to a strong strain field, such voids and microcracks are generated extensively prior to crack propagation, and the crack is largely deflected through a close-by void or microcrack. 22,23) In addition to the crack deflection, the formation of the secondary crack (as reported previously 13,14) ) induced by the block-shaped LPSO phase can contribute to enhancing the fracture toughness. Therefore, the morphological change from the thin CALs or LPSO phase to the block-shaped LPSO phase is effective in improving the fracture toughness of the RS ribbonconsolidated MgZnYAl alloys.…”

Section: Effect Of Lpso Phase Precipitation On Fracture Behaviormentioning

confidence: 58%

“…The fracture toughness test method has been described previously. 14) The microstructure was characterized by scanning electron microscopy (SEM; JEOL JSM-4601F) and transmission electron microscopy (TEM; JEOL JEM-2100F). The SEM samples were polished using a cross-sectional polishing (JEOL SM-09010).…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the line-shaped Z-contrasts and their bundles are referred to as cluster arranged layers (CALs). 14) The crystallographic orientation and grain-size distribution of the NHT alloy were investigated using EBSD. Figure 3(b), (c), (d) shows the inverse pole figure (IPF) map, KAM distribution map, and grain size distribution histogram of the longitudinal section of the NHT specimen.…”

Section: Microstructure Characterization 321 Nht Alloy Prepared From ...mentioning

confidence: 99%

“…In our previous study, we demonstrated that a preconsolidation heat treatment of the RS ribbons was effective in improving the ductility and fracture toughness of the Mg 0.85Zn2.05Y0.35Al alloy. 13,14) However, the influence of the pre-consolidation heat treatment on the multimodal microstructure evolution and toughening mechanisms has not yet been elucidated, particularly in terms of the heattreatment temperature dependence. Therefore, this study attempts to optimize the pre-consolidation heat-treatment temperature to enhance fracture toughness and to understand the mechanism.…”

Section: Introductionmentioning

confidence: 99%

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The Effects of Pre-Consolidation Heat Treatment on the Tensile and Fracture Toughness Behavior of the Rapidly Solidified Mg–Zn–Y–Al Alloys

2022

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This study is aimed to optimize the tensile properties and fracture toughness of rapidly solidified (RS) ribbon-consolidated Mg0.85Zn 2.05Y0.35Al (at%) alloys by changing the pre-consolidation heat-treatment temperature. The alloys prepared from RS ribbons heat-treated below 673 K consisting of bimodal ¡-Mg grains; coarse-worked grains (³2.8 µm) with high Kernel average misorientation (KAM) values (³1.8°), and ultrafine dynamically recrystallized (DRX) grains (³0.68 µm) with intermediate KAM values (³1.1°). The DRX grains involve cluster arranged layers (CALs) and thin plate-shaped long-period stacking ordered (LPSO) phase precipitation. The fine grain structure strengthens the alloy, significantly while they have little beneficial effects in retarding the crack propagation, thus resulting in low fracture toughness. The alloys that were heat-treated above 723 K prior to consolidation possessed a three kind of ¡-Mg grain structure; it consisted of fine DRX grains (³2.3 µm) with low KAM values (³0.5°) in addition to the coarse-worked grains and ultrafine DRX grains. The fine DRX grains improved strain hardening and ductility, resulting in fracture toughness increase. Furthermore, high-temperature pre-consolidation heat treatment produces block-shaped LPSO phase grains associated with ¡-Mg. This LPSO phase appears to work as an effective feature to toughen the materials, due to the frequent formation of microcracks in the phase and promotion of crack deflection.

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Section: Effect Of Lpso Phase Precipitation On Fracture Behaviormentioning

confidence: 58%

Section: Methodsmentioning

confidence: 99%

Section: Microstructure Characterization 321 Nht Alloy Prepared From ...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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