Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Harjo, S.; Gong, W.; 相澤 一也; 山崎 倫昭*; 川崎 卓郎
日本材料学会第58回X線材料強度に関するシンポジウム講演論文集, p.58 - 60, 2024/07
The experiment and analysis procedures for a sample exhibiting multimodal structures were outlined. The sample, a MgZnY alloy, initially comprised two phases: the HCP matrix (Mg) and the long-period stacking ordered phase (LPSO), constituting approximately 25% of the volume. Through hot extrusion at 623 K with an extrusion ratio (R) of 5.0, the alloy was rendered multimodal. Specifically, at an R value of 5.0, dynamic recrystallization occurred partially within the Mg phase, resulting in a bimodal microstructure. This microstructure consisted of a deformed Mg component and a recrystallized Mg component. An analysis employing Electron Backscatter Diffraction (EBSD) data facilitated multimodal characterization, enabling successful determination of stresses within the individual Mg components, as well as the LPSO phase stress.
萩原 幸司*; 眞山 剛*; 山崎 倫昭*; Harjo, S.; 徳永 透子*; 山本 和輝*; 杉田 三佳*; 青山 海琳*; Gong, W.; 西本 宗矢*
International Journal of Plasticity, 173, p.103865_1 - 103865_21, 2024/02
The unique control mechanisms of the plastic deformation of two-phase extruded alloy composed of Mg and long-period stacking ordered (LPSO) phase were clarified by comparison with those of other Mg solid-solution alloys, focusing on the question of why do the Mg/LPSO two-phase alloys exhibit both large elongation and high strength? The stress-strain curves for each grain in the alloys could be imaginary estimated using neutron diffraction analysis during the tensile test. The results demonstrate that the deformation behaviors of the worked and recrystallized grains are significantly different in all the Mg-extruded alloys owing to the strong plastic anisotropy in Mg with hexagonal close-packed (hcp) structure. Therefore, the deformation behavior is controlled by a composite-like deformation mechanism, even in single-phase Mg solid-solution alloys.
Harjo, 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:7 パーセンタイル:94.68(Materials Science, Multidisciplinary)An as-cast sample and two hot-extruded samples with different extrusion ratios (R) of MgZnY 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.
Harjo, 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:85.67(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.
Mthis, K.*; Drozdenko, D.*; Nmeth, 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:30.32(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 200C 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:16.35(Chemistry, Physical)Inelastic X-ray scattering (IXS) was performed on polycrystalline MgZnY and MgZnY 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.
佐野 満昭; 石井 英一; 新沼 寛明; 藤川 大輔; 真田 祐幸; 平賀 正人; 津坂 仁和; 山崎 雅直*
JAEA-Data/Code 2009-015, 142 Pages, 2009/11
幌延深地層研究計画では、第2段階の調査研究として、換気立坑,東立坑及び140m, 250m水平坑道の掘削を進めている。本調査研究では、切羽や後続施工箇所の設計・施工にフィードバックする情報化施工プログラムを実施しており、毎掘削断面において、岩相及び割れ目などの壁面観察や、簡易弾性波探査・シュミットハンマー反発度試験・エコーチップ硬さ試験及び点載荷試験等の原位置試験を行い、特定断面では地中変位測定・ロックボルト軸力測定・吹付けコンクリート応力測定及び覆工コンクリート応力測定等のデータを取得している。また、第1段階で実施した地下施設の坑道掘削に伴う湧水量の予測解析結果の妥当性を確認することを目的とし、掘削工事の進行に伴う湧水量や水質の変化に関するデータを取得した。本報告書は、2008年度(平成20年度)に実施した換気立坑(GL-161mから-250mまで),東立坑(GL-110mから-140mまで)並びに140m水平坑道で得られた調査・計測データを取りまとめたものである。
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.; 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.; 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.; 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.
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.; 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。
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.
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; 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.