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Mg and long-period stacking ordered phases in a Mg-Zn-Y alloy by hot-extrusion with low extrusion ratioHarjo, S.; Gong, W.; 相澤 一也; 川崎 卓郎; 山崎 倫昭*
Acta Materialia, 255, p.119029_1 - 119029_12, 2023/08
被引用回数：6 パーセンタイル：95.52(Materials Science, Multidisciplinary)An as-cast sample and two hot-extruded samples with different extrusion ratios (R) of Mg
Zn
Y
alloy containing the HCP matrix (Mg) and the long-period stacking ordered phase (LPSO) of about 25-vol%, were used in tensile deformation in situ neutron diffraction experiments, to elucidate the effects of uniquely different microstructural evolutions in Mg and LPSO with varying the R value to the mechanical properties. Mg behaved as the soft phase and LPSO as the hard phase, and hot-extrusion improved the strength of both. At the R value of 5.0, a bimodal microstructure was created in Mg, increasing largely the yield strength of Mg. With increasing the R value to 12.5, the bimodal microstructure of Mg collapsed and the yield strength of Mg decreased. However, the strength of LPSO increased monotonously with increasing the R value due to the developments of kink bands and texture.
Mg/LPSO dual-phase magnesium alloy monitored by 
neutron diffractionHarjo, S.; Gong, W.; 相澤 一也; 川崎 卓郎; 山崎 倫昭*; 眞山 剛*; 河村 能人*
Materials Transactions, 64(4), p.766 - 773, 2023/02
被引用回数：4 パーセンタイル：90.35(Materials Science, Multidisciplinary)To elucidate the effect of extrusion ratio in hot-extrusion on the deformation behavior during compression of MgZnY alloy containing about 25-vol% long-period stacking ordered phase (LPSO) in the HCP structured matrix (Mg), neutron diffraction measurements were performed under compressive loading using four types of samples: as-cast and after hot extrusion at 623 K with extrusion ratios of 5.0, 7.5 and 12.5. The macroscopic yielding was observed to appear by the occurrence of basal slip of Mg in the as-cast sample and at the onset of twinning in the hot extruded samples. The applied stress to initiate slip, twinning, and kinking increased by hot extrusion and then decreased with increasing extrusion ratio. LPSO shared higher stress than Mg and the ratio to the strength increased as the extrusion ratio increased.
investigation of the microstructure evolution in Long-Period-Stacking-Ordered (LPSO) magnesium alloys as a function of the temperatureM
this, K.*; Drozdenko, D.*; N
meth, G.*; Harjo, S.; Gong, W.*; 相澤 一也; 山崎 倫昭*; 河村 能人*
Frontiers in Materials (Internet), 6, p.270_1 - 270_9, 2019/11
被引用回数：7 パーセンタイル：31.21(Materials Science, Multidisciplinary)Deformation behavior of two Mg-Zn-Y magnesium alloys, having a different fraction of the long-period-stacking-ordered (LPSO) phase, has been investigated at room temperature and 200
C by a combination of neutron diffraction (ND) and acoustic emission (AE) measurements. The results indicate that the twinning in the magnesium matrix and the kinking in the LPSO phase strongly depend on the composition of the material and the testing temperature. Further, active deformation mechanisms and particularly the load transfer from the magnesium matrix to the LPSO phase define the mechanical properties of the investigated alloys.
Drozdenko, D.*; Mthis, K.*; Harjo, S.; Gong, W.; 相澤 一也; 山崎 倫昭*
Magnesium Technology 2019, p.33 - 36, 2019/02
被引用回数：0 パーセンタイル：0.07(Engineering, Chemical)The influence of the LPSO-phase orientation and the temperature on the deformation mechanisms of directionally solidified Mg-Zn-Y magnesium alloy has been investigated by neutron diffraction and acoustic emission (AE) technique. The results indicate that the kinking mechanism and activation of non-basal slip are significantly temperature and orientation dependent with respect to the loading axis.
細川 伸也*; 木村 耕治*; 山崎 倫昭*; 河村 能人*; 吉田 亨次*; 乾 雅祝*; 筒井 智嗣*; Baron, A. Q. R.*; 川北 至信; 伊藤 晋一*
Journal of Alloys and Compounds, 695, p.426 - 432, 2017/02
被引用回数：3 パーセンタイル：16.72(Chemistry, Physical)Inelastic X-ray scattering (IXS) was performed on polycrystalline MgZn
Y
and Mg
Zn
Y
alloys with synchronized long-period stacking ordered (LPSO) phase for investigating the impurity effects in the microscopic elastic properties. Inelastic neutron scattering (INS) was also carried out on the former alloy. LA modes were clearly observed in the IXS spectra of both the LPSO alloys, while TA modes can mainly be detected in the second Brillouin zone. Broader inelastic signals and larger quasielastic peaks are characteristic due to the phonon scattering by the Zn/Y impurities. Only the TA excitation energies increase by adding the impurities, which indicates a harder stiffness of the bond angles relating to the L1-type clusters in the LPSO alloys. New dispersion-less excitation modes are observed at about 10 meV by adding the Zn/Y impurities. By comparing with the INS data, the contributions of the impurities to these excitations are discussed using differences in the scattering cross-sections between neutrons and X-rays.
ZnY内のMgとLPSO間の応力分配と押出比の関係Harjo, S.; 相澤 一也; Gong, W.*; 川崎 卓郎; 山崎 倫昭*; 河村 能人*
no journal, ,
押出比が異なる高温押出したMgZnY合金を室温で引張変形させならその場中性子回折実験を行った。高温押出によるMgとLPSOの集合組織の変化及び変形中の両相間の相応力分配を調べて、強化機構を議論する。
Harjo, S.; 相澤 一也; 川崎 卓郎; Gong, W.; 山崎 倫昭*; 河村 能人*
no journal, ,
MgZnY alloy is a magnesium alloy consisting an Mg phase as the matrix and a Long-Period Stacking Ordered (LPSO) phase with the volume fraction of about 25%. In situ neutron diffractions during compression at room temperature of MgZnY alloys in as-casted condition and hot-extruded conditions with the extrusion ratios of 5.0, 7.5 and 12.5 were conducted to elucidate the deformation mechanism after hot-extrusion. The evolutions of integrated intensities of diffraction peaks, lattice strains of individual constituent phases measured from neutron diffraction were plotted with the applied stress and strain, and twinning in Mg and kinking in LPSO phase were discussed.
ZnY内のMgとLPSO間の応力分配と押出比の関係Harjo, S.; 相澤 一也; Gong, W.; 川崎 卓郎; 山崎 倫昭*; 河村 能人*
no journal, ,
LPSO相が約25%含まれたMgZnY合金について、高温押出後に圧縮変形させながらin situ中性子回折によってMg相とLPSO相それぞれが分担する応力を調べ、押出比(R)を大きくした時のLPSO相の強度について解明した。高温押出によってMg相の降伏応力が増大したが、Rが5.0から12.5になるとMg相の降伏応力が小さくなった。しかしながら、巨視の降伏近傍ではLPSOの相応力はRが大きくなるに伴い大きくなった。これは、LPSO相の強度がRの増加によって低下しないことを表している。
Harjo, S.; Gong, W.; 相澤 一也; 川崎 卓郎; 山崎 倫昭*; 河村 能人*
no journal, ,
Interesting mechanical properties changes were found in MgZnY alloy containing about 25-vol% long-period stacking ordered phase (LPSO) in the HCP structured matrix (Mg), by hot-extrusion. In situ neutron diffraction measurements during tensile loading were conducted on three MgZnY alloys with different processes: as-casted, and after hot-extrusion at 623 K with extrusion ratios of 5.0 and 12.5, to elucidate the relation between the changes in microstructure by hot-extrusion with the changes in mechanical property. The yield strength of Mg increased by the hot-extrusion, but when the extrusion ratio increased the Mg yield strength ironically decreased. LPSO was found to be strengthened monotonically as the extrusion ratio increased.
Harjo, S.; 相澤 一也; Gong, W.; 川崎 卓郎; 山崎 倫昭*; 河村 能人*
no journal, ,
The MgZnY alloy, a magnesium alloy with a duplex microstructure consisting of an phase (Mg) and a long period stacking ordered phase (LPSO) of approximately 25 vol.%, showed high strength and high ductility after hot extrusion at 623 K. To understand tensile deformation behavior of each phase and effect of kinks to the strength of the alloy, we have performed in situ neutron diffraction measurements during tensile tests of the alloys in an as-cast condition and after extruded at 623 K with different extrusion ratios.
Harjo, S.; Gong, W.; 川崎 卓郎; 相澤 一也; 山崎 倫昭*
no journal, ,
押出したLPSO型マグネシウム合金は、引張変形と圧縮変形ではLPSOへのキンク導入などについて異なる挙動を示すことがその場中性子回折実験から観察された。本研究では、押出したLPSO型マグネシウム合金の繰り返し引張圧縮変形中のその場中性子回折観察を行い、変形挙動を調べた。繰り返し変形中のMg相のマイクロひずみの変化は強度変化の傾向と一致した。一方、LPSO相のマイクロひずみは最初の変形で大きく増加したがその後のサイクルでは変化しなかった。
ZnY内のMgとLPSO間の応力分配Harjo, S.; 相澤 一也; Gong, W.; 川崎 卓郎; 山崎 倫昭*
no journal, ,
MgZnY合金は、Mg相とLPSO相の相分率が約25%からなる二相組織を持つLPSO型マグネシウム合金である。高温押出したMgZnY合金の繰り返し引張圧縮変形中のその場中性子回折による観察を行い、圧縮変形でのLPSO相のキンク変形と強度への効果について調べてみた。負荷ひずみが+0.01-0.02のサイクル実験での引張の最大応力は、2サイクル目では1サイクル目に比べると大きくなり、その増加量は負荷ひずみが+0.01-0.01の条件に比べて大きかった。構成相のそれぞれの集合組織,格子ひずみ等より相応力等を評価して圧縮変形でのLPSO相のキンク変形と強度への効果について詳細検討を行う。
Harjo, S.; 相澤 一也; Gong, W.; 山崎 倫昭*; 川崎 卓郎
no journal, ,
The elongation of an LPSO type Mg alloy consisting 25 vol% of LPSO phase was found to increase without sacrificing the tensile strength, when the extrusion ratio or the equivalent strain of the hot-extrusion became higher. This phenomenon is very interesting, considering that the improvements of elongation and of tensile strength due thermo-mechanical processes are usually contradictory properties. In this study, monitoring deformation behavior of the Mg and LPSO phases in hot-extruded LPSO type Mg alloys consisting 25 vol% of LPSO phase by in situ neutron diffraction was carried out to elucidate the reason of the improvement of both elongation and strength by hot-extrusion with high extrusion ratio.
Mg/LPSO dual phase alloy by hot-extrusion using in situ neutron diffraction during deformationHarjo, S.; 相澤 一也; Gong, W.; 川崎 卓郎; 山崎 倫昭*
no journal, ,
In this study, in situ neutron diffraction during deformation was performed using three kinds of samples of MgZnY alloy: an as-casted sample (As-Cast), hot extruded samples with the extrusion ratio (R) values of 5.0 (R=5.0) and 12.5 (R=12.5). Crystallographic evolutions of Mg and LPSO phases by hot-extrusion and deformation behavior of the individual phases were investigated, and the unique deformation mechanism by hot-extrusion in this alloy will be discussed based on the obtained results.
Harjo, S.; Gong, W.; 川崎 卓郎; 相澤 一也; 山崎 倫昭*
no journal, ,
An in situ neutron diffraction experiment during cyclic tension-compression with an applied strain of 
0.01 and was conducted at room temperature using a MgZnY alloy, after hot-extrusion at 723 K with the extrusion ratio of 10, to understand the deformation behavior of both Mg and LPSO phases and to elucidate kinking in the LPSO phase including its effect to the strength during the cyclic tension-compression deformation. The evolutions of textures, lattice strains of individual constituent phases measured from neutron diffraction will be plotted with the applied stress, strain and the cyclic number, and details will be presented in this presentation.
Harjo, S.; Gong, W.; 川崎 卓郎; Mao, W.; 山崎 倫昭*
no journal, ,
Many advanced metallic materials composed of not only multiphases but also multi-morphological structures within one of the constituent phases, so-called multimodal structure metallic material. In this presentation, we will introduce and discuss our methods to understand the deformation behavior in metallic materials with multimodal structure, using a case of strengthening of Mg and long-period stacking ordered phases in a Mg-Zn-Y alloy by hot-extrusion with low extrusion ratio.
Harjo, S.; Gong, W.; 山崎 倫昭*; 川崎 卓郎; 相澤 一也
no journal, ,
An as-cast sample and two hot-extruded samples with different R values of MgZnY alloy, the Mg-LPSO alloy containing LPSO of about 25-vol%, were used in tensile deformation operando neutron diffraction experiments. Mg behaved as the soft phase and LPSO as the hard phase, and hot-extrusion improved the strength of both. At the R value of 5.0, dynamic recrystallization partly occurred in Mgg creating a bimodal microstructure, consisting of the deformed Mg microstructure and the recrystallized Mg microstructure. The yield strength of Mg was significantly improved due to the optimal effects of dislocation density accumulation and texture development in the deformed Mg microstructure, and grain refinement in the recrystallized Mg microstructure.
