材料期刊网

INTERNAL FRICTION AND MODULUS DEFECT ASSOCIATED WITH THE MICROCRACKS IN MATERIALS

Q.F.Fang Laboratory ofInternal Friction and Defectsin Solids , Institute of Solid State Physics , The Chinese Academy of Sciences , Hefei230031 , China

金属学报(英文版)

Inthis paper, theinvestigation of applying internalfriction ( ultrasonic attenuation) andmodulus defect(ultrasonic velocity change) tostudy the variation of dislocation density andlooplength withcycle numberintheearly fatiguestageisreviewed. On this basis,thecon ceptof characterization of fatigue microcrackformation and propagation assessed bythe mea surementofinternalfriction and dynamicalelastic modulusissuggested. Theanalyticalex pressionoftheinternalfriction and modulus defect associated with microcracksiscalculated underthe assumptionthatthe mechanicalenergy dissipation iscaused by the mutualfriction betweentheoppositefacesofthe microcrack.

关键词: internalfriction , null , null

Conceptual design of Hefei advanced light source

中国物理C

关键词:

Conceptual design of Hefei Advanced Light Source(HALS)injection system

中国物理C

关键词:

Controversy about the Origin of the Grain Boundary Internal Friction Peak and Its Clarification

T.S.Ke (Tingsui GE)(Lab. of Internal Friction and Defects in Solids , Institute of Solid State Physics , Chinese Academy of Sciences , Hefei 230031 , 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: