YIN Zhongda Harbin Institute of Technology
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Harbin
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China ZHOU Yongkang Shanghai Centrifugal Machinery Research Institute
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Shanghai
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China YIN Zhongda Faculty of Heat Treatment of Materials
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Harbin Institute of Technology
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Harbin 150006
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China
金属学报(英文版)
An approach to study the recrystallization-induced plasticity(RIP)phenomenon in the 18Ni maraging steel under the elastic stress has been made by the analysis of dynamic behaviour at elevated temperatures,the phenomenological analysis of dynamic strain feature curves,the confirmation of phase transformation point and TEM observation of RIP processing itself.
关键词:
elastic stress
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LIU Jianhong HE Shiyu YAO Mei Harbin Institute of Technology
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Harbin
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China lecturer
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Depatment of Metallic Materials
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Harbin Institute of Technology
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Harbin 150006
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China
金属学报(英文版)
The growing process of thermal fatigue cracking,in steel 3Cr2WSV was observed under desk SEM fitted with sell-made minisized device for thermal faligue test.Before the growing of thermal fatigue crack,the main crack tip reveals to blunt firstly,and some holes and uncontinuous microcraeks occur in front of it.The growth is developed by bridging of main crack together with holes and microcracks.
关键词:
steel 3Cr2W8V
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null
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SUN Dongli YANG Dezhuang LEI Tingquan CUI Yuexian Harbin Institute of Technology
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Harbin
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China Lecturer
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Department of Metallic Materials and Technology
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Harbin Institute of Technology
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Harbin 150006
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China
金属学报(英文版)
The fracture mechanism of deformation-aged Al-Li alloy was approached by investigating the influence of prior cold deformation on the precipitation kinetics as well as the behaviours of work hardening and fracture for Al-2.73Li alloy.The experimental results show that the work hardening rate and the strength are increased and the ductility is decreased by prior cold deformation.The decrease in ductility is mainly due to the cell dislocaton substructure distrib- uted inhomogeneously and the hardening of precipitate free zones at grain boundaries caused by prior cold deformation.The failure mode in the alloy is a mixed integranular and transgranular one.The tendency of intergranular fracture is intensified through the deformation-aging.The mechanisms of intergranular failure in the alloy are different under various deformation-aging treatments.
关键词:
Al-Li alloy
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null
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LIU Qing HUANG Xiaoxu YAO Mei YANG Jinfeng Harbin Institute of Technology
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Harbin
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China Department of Metals and Technology
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Harbin Institute of Technology
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Harbin 150006
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China
金属学报(英文版)
A much higher elongation of a warm rolled superplastic Al-Li-Cu-Mg-Zr alloy was made under two-stage strain rate tests comparing with the single ones.During initial stage of deformation a deformation-induced continuous recrystallization which converted a subgrain structure into a recrystallized grain structure by a continuous increase in boundary misorientations had occurred.The higher the strain rate,the faster the continuous recrystallization and the finer the recrystallized grains.The fine recrystallized grain structure formed during the first stage deformation is the essential condition for the material to have high strain rate hardening and strain hardening during the low second stage superplastic deformation.The combination of strain rate hardening and strain hardening is the reason why the higher elongation may be obtained during two-stage superplastic deformation of the alloy.
关键词:
Al-Li alloy
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null
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LIANG Guoxian WANG Erde HUO Wencan Harbin Institute of Technology
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Harbin
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China Post Box 435
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Harbin Institute of Technology
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Harbin 150006
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China
金属学报(英文版)
Ni_(100-x)Mo_x(x=20,30,38)alloys have been synthesized by mechanical alloying.The structure evolution of powders in mechanical alloying process has been monitored by X-ray diffraction,scanning electron microscopy and transmission electron microscopy analyses.The results show that the Ni_(62)Mo_(38)sample becomes partially amorphous after high energy ball milling,while the Ni_(80)Mo_(20)and Ni_(70)Mo_(30)become non-equilibrium nanocrystals.
关键词:
mechanical alloying
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JIANG Bailing LEI Tingquan LIU Wei CUI Yuexian Harbin Institute of Technology
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Harbin
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China Dept.of Metallic Materials and Technology
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Harbin Institute of Technology
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Harbin 150006
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China
金属学报(英文版)
The TEM observation on the single-side thinned specimens was made of the nucleation and growth of boride during boronization for steel 20 and the influence of prior room temperature deformation.The results of X-ray diffraction and electron probe microstructure analysis show that only Fe_2B formed in the surface layer of specimens at the beginning of boronization;the atomic concentration of B in the surface layer increased with the increase of deformation monotonously;and the segregation of B atoms in the dislocation cells hindered the recovery and recrystallization of the deformed structure of the matrix and accelerated the nucleation and growth of boride in the surface layer.
关键词:
boronization
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