Microstructure of Explosively Bonded Metals as Observed by Transmission Electron Microscopy (1st Report) Low carbon-steel clad and austenitic stainless clad steel

• Published in: JOURNAL OF THE JAPAN WELDING SOCIETY Vol. 42; no. 6; pp. 518 - 525
• Main Authors: Yamashita, Tadayoshi, Onzawa, Tadao, Ishii, Yugoro
• Format: Journal Article
• Language: Japanese
• Published: JAPAN WELDING SOCIETY 25.06.1973
• ISSN: 0021-4787; 1883-7204
• DOI: 10.2207/qjjws1943.42.518

Microstructure of explosively bonded composites, low carbon-steel to low carbon-steel and austenitic stainless steel to low carbon-steel, has been investigated by transmission electron microscopy. The bond zone whose width is less than several μ consists of a mixture of a clad metal and a base metal, and the small crystal grains in each component metal are several thousand Å in size. Both areas within about 10 μ from the bond zone are composed of either small crystal grains or elongated grains of several thousand Å width. Dislocation density in these areas as well as the bond zone is of the order of 109/cm2. Larger crystal grains at distance of 10-600 μ from the bond zone has a dislocation density of 1010-1011/cm2, and the dislocation density at further increased distance is 109-1010/cm2. There exist tangled dislocations with cusps, dislocation loops and undeveloped cell structure. Thin deformation twins in austenitic stainless steel and elongated subgrains resulting from α→ε→α transformation of low carbon-steel are observed profusely. No significant hcp ε-phase is detected in the stainless steel. The adequacy of the proposed mechanism of the explosive bonding based on the theory of compressible fluid is discussed from the result obtained.