D. Liu
,
Y.H. Yang
,
J. Geng
,
Z.J. Luo
,
null
,
null
金属学报(英文版)
The interaction between thermomechanical parameters and microstructure evolution is so intense that it must be considered during the finite element method (FEM) simulation of the hot plastic working process, for materials that are difficult to deform. Taking the microstructure evolution into account, a novel type of constitutive relationship has been put forward for the IN718 alloy. The microstructure evolution model was first established for the dominant microstructure evolution processes. Then the microstructure evolution models and the method to determine the local flow stress of the corresponding microstructure for current thermomechanical parameters and deformation history were presented. Once the local flow stresses of different structures and their volume contributions were defined, the apparent flow stress of the material could be determined as the weighted sum of the local flow stresses and volume contributions. To validate the proposed method, a thermoviscoplastics and microstructure evolution coupled analysis for a forging process of a critical IN718 disk forging was performed. The predicting results were in close agreement with the experimental data.
关键词:
constitutive relationship
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null
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null
S.Q. Deng
,
Z.P. Xue
,
Y.H. Yang
,
Q. Yang
,
Y.L. Liu
材料科学技术（英文）
Well dispersed and homogeneous Y2O2S:Sm3+ hollow submicrospheres were successfully achieved by a template-free solvothermal method combining with a postcalcining process. The crystalstructure and particle morphology were investigated by the X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, scanning and transmission electron microscopy (SEM and TEM), respectively. A possible growth mechanism was proposed to reveal the formation process. Luminescence properties of the Y2O2S:Sm3+ long-lasting phosphor were analyzed by measuring the excitation spectra, emission spectra, afterglow decay curve and thermoluminescence curve. The excitation spectra indicated that the phosphor could be excited effectively by the ultraviolet-light emitting diode (UV-LED) or blue LED, and the emission spectra showed that the phosphor could emit red light from 600 to 650 nm.
关键词:
Yttrium oxysulfide
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null
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null
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null
