T.S.Ke (Tingsui GE)(Lab. of Internal Friction and Defects in Solids
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Institute of Solid State Physics
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Chinese Academy of Sciences
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Hefei 230031
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China)
材料科学技术（英文）
In the seventies some scientific workers from France and ltaly suggested that the grain boundary internal friction peak (named the Ke peak in the literature) widely accepted as a grain bound ary process, is originated from the motion of lattice dislocations. Since this problem is one of fundamental importance, this controversy has drawn much international attention. Started from 1982, the Hefei research group made a critical analysis of the large amount of literature concerning this problem and performed a series of crucial experiments to clarify the controversy It is concluded that the irrelevant evidence suggested by the controverters comes from the farfetched interpretation and the mis-identification of the internal friction peaks appeared under various experimental conditions and different states of the specimens.
关键词:
JI Jingwen LAI Zuhan WU Yuqin ZHANG Guofu Northeast University of Technology
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Shenyang
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ChinaLI Guangyi Institute of Metal Research
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Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
The strong effect of rare earth(RE)on medium-temperature internal friction(IF)of commercially pure iron is closely related to the heat treatment.The RE added into iron has an alloying effect.The Snoek-Ke-Kster(briefly SKK)peak lower as the aging temperature in- creases from 150℃ to 450℃,but it still exists even aged at 600℃.However,the SKK peak temperature T_p does not simply falls as the ascending of aging temperature,it rises again at 600℃ aging.
关键词:
internal friction
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null
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材料科学技术（英文）
The 304 stainless steel with nanostructured surface layer was successfully obtained by using the high-energy shot peening (HESP) method. The internal friction and Young's modulus of this kind of surface nanocrystallized material were dynamically measured by means of the vibrating reed apparatus. The results implied that different treatment time could induce different microstructure and distribution characteristic of defects in this kind of materials. It is also demonstrated that there is a transition layer between the nano-layer on surface and the coarse grain region inside. The transition layer obviously has certain influence on the overall mechanical properties.
关键词:
surface nanocrystallization;internal friction;high-energy shot peening;iron;behavior
Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
In this paper, 304 stainless steel and pure Fe specimens, which were processed by high-energy shot peening (HESP) and ultrasonic shot peening (USP) respectively, were studied by the internal friction method. Measurements were carried out on a vibrating reed apparatus. The change of internal friction and elastic modulus shows that the treatment duration of specimen is not accompanied by the corresponding persistent increase of internal friction and elastic modulus. There is a transition layer from the top surface to the inside of the materials. Young's modulus of surface shows obviously a fluctuation along the depth profile. The phenomena have never been shown by other measurement methods. The microstructure change should be related to some basic mechanism of surface layer formation. It may also explain why the improvement of mechanical properties in surface nanocrystallized materials does not simply correspond to the duration time of severe deformation. (C) 2003 Elsevier B.V. All rights reserved.
关键词:
internal friction;Young's modulus;surface nanostuctured material;iron;nanocrystallization;304-stainless-steel;behavior
JI Jingwen WEI Quanjin GENG Dianqi WU Yuqin Northeast University of Technology
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Shenyang
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China Professor
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Dept.of Physics
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Northeast University of Technology
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Shenyang 110006
,
China
金属学报(英文版)
The grain boundary internal friction(GBIF)in Fe-P and Fe-P-La alloys containing trace Cu has been studied.It is found that an addition of 0.584—0.722 wt-% La obviously reduces the IF,shifts grain boundary peaks towards higher temperatures,and produces a small addi- tional peak at even higher temperature.The mechanism of GBIF is explained as the movement of defects of atomic size,namely point defects,at gram boundaries and/or their clusters un- der stress.
关键词:
internal friction
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null
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Journal of Materials Science
Internal friction and modulus at different amplitudes and frequencies were measured for as-cast Mn60Cu40 alloy. Strong non-linear internal friction and resonance were observed. It was proposed that the sources of these were derived from different factors. A parameter, P, which can be used to weigh up non-linear resonance of materials, is proposed. A high damping mechanism is discussed for manganese-copper alloy.
关键词:
Y.L. Chen(Department of Materials Science and Engineering
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Zhejiang University
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Hangzhou 310027
,
China)
金属学报(英文版)
Internal friction measurements on binary and ternary α-phase alloys of Pd with hydrogen and boron have been performed with a torsion pendulum and by observing the cttenuation of ultrasonic pulses. A pronounced damping maximum of binary Pd-B alloys at 220K and measuring frequencies of about 4Hz could not be established at a frequency of 15MH. Ternary Pd-B-H alloys show an additional damping maximum besides the hydrogen Zener effect, which is interpreted in terms of a changed jump frequency of hydrogen in the neighborhood of boron atoms.
关键词:
Pd-B-H alioy
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null
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null
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Wenmao HUANG
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Haihong ZHAN
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Lingyan XU
,
Zhengbing XU
,
Jianmin ZENG
金属学报(英文版)
doi:10.1016/S1006-7191(08)60091-5
TiB2/ZL114 composites with the density of 2.733 g/cm3 were fabricated through reaction of K2TiF4 and KBF4 (LSM method). The composites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The internal friction measurements were performed on DTM-II-J dynamic modulus damping analyzer and the mechanisms were investigated. Experimental results indicate that reinforced particles are well-distributed in the matrix and the internal friction value of TiB2/ZL114 composites is up to a maximum of 9.04x10-3, almost twice that of ZL114. The internal friction results form dislocation vibration within the material, the sliding of grain boundary and phase interface, and together with the micro-plastic deformation caused by difference in coefficients of thermal expansion and elasticity modulus of various phases. The average internal friction values of samples with the sizes of 40 mmx4 mmx2 mm, 40 mmx8 mmx2 mm and 40~mm$\times 25 mmx2 mm are 8.83x10-3, 8.89x10-3, and 8.93x10-3, respectively. Thus, the developed composites are of low density, high internal friction, and the sizes of samples have no relation to the internal friction behavior.
关键词:
LSM method
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null
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XIA Yuebo ZHANG Tianyi State Key Laboratory for Fatigue and Fracture of Materials
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Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaFEI Guangtao ZHOU Xing Laboratory of Internal Friction and Defects in Solids
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Institute of Solid State Physics
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Academia Sinica
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Hefei
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China Associate Professor
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Institute of Metal Research
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Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The variation of cyclic stress,internal friction and ultrasonic attenuation during cyclic deformation and relations among them have been investigated with different slip orientation Al single crystals.The results indicate that the value of cyclic stress σ,internal friction Q~(-1)and ultrasonic attenuation △α depend obviously on the slip orientation.There are large differences in above three parameters for different slip orientation Al crystals.In early stage of fatigue life,σ and △α increase and Q~(-1)decreases with cycles N,and △α reached maxi- mum before σ,while Q~(-1)and σ get the valley and the peak,respectively,at same cycles.
关键词:
crystal orientation
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