日本金属学会誌

J. Japan Inst. Metals, Vol. 62, No. 8 (1998),
pp. 742-747

Observation of Impurity Hydrogen Evolved from Aluminum during Deformationby Means of Silver Decoration Technique

Katsumi Koyama1, Goroh Itoh2 and Motohiro Kanno3

1Fukui Research Laboratory, The Furukawa Electric Co., Ltd., Fukui 913-8588
2Department of Mechanical Engineering, Nagaoka University of Technology, Nagaoka 940-2188

3Department of Materials Science, School of Engineering, The University of Tokyo, Tokyo 113-8656

Abstract:

Silver decoration technique was applied to high purity aluminum specimens with two impurity hydrogen levels to visualize the hydrogen atoms evolved from the specimen during tensile deformation. The specimens were deformed by about 5% in the silver decoration solution of K[Ag(CN)2]. A number of needle-shaped deposits indicating hydrogen evolution were revealed along coarse slip lines produced by the deformation. The deposits were identified by AES not as metallic silver but as AgCN crystals. The amount of the deposits was affected significantly by the impurity hydrogen content of the specimen and by pH and temperature of the silver decoration solution, but not markedly by K[Ag(CN)2] concentration in the solution. This new method using silver decoration technique is a relatively simple and valuable tool for the study of hydrogen embrittlement of metals and alloys.


(Received April 6, 1998; In Final Form June 1, 1998)

Keywords:

pure aluminum, impurity hydrogen, hydrogen evolution, hydrogen transport, deformation, silver decoration technique, dislocation, slip line, grain boundary


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