210303 硬脆性材料拡散接合部の微細組織変態を利用した靱性改善(OS15 生産加工3,オーガナイズド・セッション)

概要

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In general, the diffusion-bonded joint of hard and brittle materials has the low impact resistance. The grain-boundary arranged flatly near the former mating surface is considered to suppress the toughness of the diffusion-bonded joint. In order to improve its impact resistance, the phase-transformation was deliberately induced to encourage the displacement of the grain-boundary at the bonding interface. The tool steel (SKD61 in JIS) square bars were diffusion-bonded at higher temperature than the austenitizing temperature, followed by the various heat treatment to induce the martensitic, bainitic and pearlitic transformations. By the martensitic transformation after the diffusion bonding process, the joints had the comparable Charpy impact value with the bulk material which experienced the same heat treatment. The optical observation of the microstructure revealed that the flat grain-boundary was vanished due to the growth of the martensitic microstructure. The results showed the effectiveness of the successive phase transformation process just after the diffusion bonding process.
一般社団法人日本機械学会の論文
2011-03-17