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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 Mg
Zn
Y
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.
Harjo, S.; Gong, W.; 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.51 - 54, 2024/07
In-situ neutron diffraction was used to study tensile deformation in an extruded AZ31 alloy. The aim was to validate existing methods and develop new ones for stress evaluation in magnesium alloys. Results showed varied increases in lattice strains among grains, posing challenges for conventional procedures. A new method, considering grain volume fraction and multiple orientations, proved highly accurate. When simultaneous hk.l peaks weren't available, the 12.1 peak was recommended for stress evaluation, showing a linear relationship with applied stress throughout deformation.
Harjo, S.
Isotope News, (793), p.13 - 16, 2024/06
高強度マグネシウム(Mg)合金の高温押出加工による大幅な強度増加の機構を引張変形その場中性子回折実験によってどのように解明したかについて紹介する。高温押出加工の条件により組織が複雑化し、構成相それぞれの組織からの強度への寄与について解説する。
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：8 パーセンタイル：72.13(Materials Science, Multidisciplinary)To elucidate the effect of extrusion ratio in hot-extrusion on the deformation behavior during compression of MgZn
Y
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.
清水 一行*; 林田 洋寿*; 戸田 裕之*; 甲斐 哲也; 松本 吉弘*; 松本 佳久*
日本金属学会誌, 83(11), p.434 - 440, 2019/11
被引用回数：1 パーセンタイル：5.13(Metallurgy & Metallurgical Engineering)Neutron imaging experiment was performed to visualize the distribution of solute hydrogen in an Al-10.1%Zn-1.2%Mg alloy and a pure palladium after hydrogen charging. Changes in the contrast of neutron transmission images caused by hydrogen were clearly observed in a palladium. In the wavelength range of 2-3 AA and 5-13.5 AA, the mean neutron transmission around the center of a hydrogen-charged palladium were 0.692 and 0.511, respectively. The hydrogen content in a palladium was estimated to be 10.8 mol% from the measured neutron transmission. This study has demonstrated that hydrogen content can be analyzed by considering the wavelength dependence of neutron intensity. On the other hand, hydrogen could not be observed from the neutron transmission image in Al-Zn-Mg alloys. This was due to the low hydrogen content, which was mass ppm level even after hydrogen charging, and statistical precision was not sufficient to discuss the amount of hydrogen of the mass ppm order.
白石 健介
Trans.JIM, 11(6), p.440 - 441, 1970/00
抄録なし
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.; 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.
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.
