A novel long-period stacking/order structure in Mg-Ni-Y alloys

Yamashita, K.; Itoi, Takaomi; Yamasaki, Michiaki; Kawamura, Yoshihito; Abe, Eiji

doi:10.1016/j.jallcom.2019.02.219

Cited by 37 publications

(17 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Zn6Y8) as deviated from the original L12-order of 3:1 (L12-Zn3Y). In fact, it is experimentally confirmed that the LPSO composition range shows up with a definite pseudo-binary behavior well bound along the Zn/Y ratio of 3/4[7,10,12], supporting well the robust Zn6Y8-cluster characteristics[47]. Although the present calculations cannot reproduce precisely the experimental Zn/Y ratio (~3/4) due to a limitation of the principle framework (i.e., we considered only the simple fcc order and did not the superlattice Zn6Y8-cluster order), the pseudo-binary behaviors are nevertheless emerged with the definite tie-line between the almost pure-Mg and the L12-order phases (Figs.…”

mentioning

confidence: 79%

“…Even though the stoichiometric LPSO structures have been well established as the sufficiently stable phase, the thermodynamic origin of the LPSO phase is not fully understood yet. It is found that the LPSO phases form with non-stoichiometry compositions widely extended into TM/RE dilute ranges, as being significantly far from the ideal LPSO stoichiometry [7,10,12] and bound along the definite TM/RE ratio due to the robust L12-type SRO clusters. In such dilute compositions, the LPSO phase may behave as solid solutions rather than a stoichiometric compound.…”

Section: Introductionmentioning

confidence: 99%

“…synchronized LPSO polytypes of 12R [11,12], 10H, 18R, 14H and 24R [6] have been identified so far. It is rather surprising that such largely anisotropic crystals are able to contribute for materials strengthening, since the isotropic/high-symmetry crystals with sufficient dislocation-slip systems are primary chosen for the use of structural materials.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermodynamic Origin of Solute-Enriched Stacking-Fault in Dilute Mg-Zn-Y Alloys

et al. 2019

Self Cite

View full text Add to dashboard Cite

We investigate thermodynamic behaviors of dilute Mg-Zn-Y ternary alloys to form a unique solute-enriched stacking-fault (SESF), which is an intrinsic-II type stacking-fault (I2-SF) enriched by the Zn and Y atoms and represents the structural-unit of the long-period stacking/order (LPSO) phase. SESF in the hexagonal-close-packed (hcp) Mg matrix forms a local face-centered-cubic (fcc) environment, and hence our thermodynamic analysis is based on the Gibbs energy comparison between hcp and fcc phases over the Mg-Zn-Y ternary composition ranges, using the calculation of phase diagrams (CALPHAD) method aided by the first principles calculations. Segregation behaviors of solute Zn/Y atoms into the SESF are firstly estimated according to the Hillert's parallel tangent law, followed by the possible disorder-order phase transformation within the SESF using the multiple-sublattice model. We find that the Zn/Y co-segregations at the SESF provide a remarkable condition that the fcc layers become more stable than the hcp-Mg matrix. Besides, within the SESF, the following spinodal-like decomposition into the Mg-rich solid-solution and the Zn/Y-rich L12-type order phase causes a significant reduction of the total Gibbs energy of the system. These thermodynamic behaviors explain fairly well a phenomenological origin of the Zn-Y clustering with the L12-type short-range order, which is known to occur for the LPSO phases and also confirmed for the present SESF by electron microscopy experiments.Therefore, strong Zn-Y interactions even in dilute conditions play a key role to stabilize firmly the SESF in the Mg-Zn-Y alloys.Keywords: Magnesium alloys; thermodynamic analysis; calculation of phase diagrams (CALPHAD); solute-atom clustering; scanning transmission electron microscopy A.1. Gibbs energy of hcp and fcc solution phases 1 2,4 5 and 1 2,4,6 5 in eq. (5) represent the interaction parameters in the i-j binary and i-j-k ternary systems, respectively, which are described as following equations;

show abstract

mentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermodynamic Origin of Solute-Enriched Stacking-Fault in Dilute Mg-Zn-Y Alloys

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is also noted that different local ordered structure at the domain boundaries may form due to the translations between different 6M superstructure in domains. For example, in P 3 type patterns in Figure 3(c), the inter-cluster spacing may form locally 7M ordered structure as observed in [24]. Nevertheless, the domain structures in the LPSO structure have been observed in high alloyed Mg 85 Zn 6 Y 9 alloy by scanning tunneling microscopy [25,26], but its link to the ordering process of the LPSO structures has not been revealed.…”

mentioning

confidence: 98%

“…Within these rectangles, there are other three new type patterns of clusters as denoted by P 1 , P 2 and P 3 , which are frequently observed in the transitional state during ordering of the LPSO structures. Furthermore, according to the diffraction patterns in [24]. Furthermore, the distance between L1 2 clusters in P 0 type patterns can be directly measured in the HAADF-STEM image as in Fig.…”

mentioning

confidence: 99%

Domain structures and the transitional state of ordering in long-period stacking ordered (LPSO) structures in Mg–Al–Gd alloy

Chen

Yang

2020

Scripta Materialia

View full text Add to dashboard Cite

The transitional state of ordering in the long-period stacking ordered (LPSO) structure in Mg-Al-Gd alloy has been investigated by scanning transmission electron microscopy. It is found that the domains are the origin of observed transitional state.Three new patterns of clusters at this state can be fully explained by the superimposition of L1 2 type clusters located in different domains. The domains are further verified by different tilted views. Growth of preferred domains during ageing process will result in final ordered LPSO structure. Based on the idea of domains, less ordered LPSO structure in other dilute alloys can be also understood.

show abstract

Microstructure and Mechanical Properties of Mg–Er–Cu/Ni/Zn Alloys with Long Period Stacking Ordered Phases

Zhang

Ouyang

et al. 2021

Adv Eng Mater

View full text Add to dashboard Cite

The microstructure and mechanical properties of as‐cast Mg96Er3Cu1, Mg96Er3Ni1, and Mg96Er3Zn1 alloys prepared by conventional ingot metallurgy are investigated. Results show that the bulk 18R long period stacking ordered (LPSO) phases in all three as‐cast alloys solidify directly from the melt. The grain size of the Mg96Er3Zn1 alloy is the smallest; the volume fraction of the LPSO phase in the Mg96Er3Ni1 alloy is the highest in all three alloys due to negligible Ni solid solubility in α‐Mg. The thermal stability of the 18R LPSO phase in the as‐cast Mg96Er3Ni1 alloy is much higher than in the other two alloys. Tensile tests indicate that the as‐cast Mg96Er3Zn1 alloy shows the best ductility; the as‐cast Mg96Er3Ni1 alloy possesses the highest tensile strength, and the ultimate tensile strength and yield tensile strength are 245 and 149 MPa, respectively, accompanied by a good elongation of 7.1%.

show abstract

A novel long-period stacking/order structure in Mg-Ni-Y alloys

Cited by 37 publications

References 21 publications

Thermodynamic Origin of Solute-Enriched Stacking-Fault in Dilute Mg-Zn-Y Alloys

Thermodynamic Origin of Solute-Enriched Stacking-Fault in Dilute Mg-Zn-Y Alloys

Domain structures and the transitional state of ordering in long-period stacking ordered (LPSO) structures in Mg–Al–Gd alloy

Microstructure and Mechanical Properties of Mg–Er–Cu/Ni/Zn Alloys with Long Period Stacking Ordered Phases

Contact Info

Product

Resources

About