焼結鉄の靭性ならびに寸法変化の異方性に関する考察

概要

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Cylinders, d40 mm×h40 mm for small-sized Charpy specimens and d10 mm×h10 mm for electrical conductivity measurements during compacting, and 10 mm cubes for dilatometry were compacted. Electrolytic and reduced-ore iron powders were pressed by admixing 0.7 mass% of zinc-stearate, or by die-wall lubricating alone under 98-588 MPa, de-waxed at 600°C for 30 min, anc sin tered at 1100°C for 60 min in dissociated ammonia. Small-sized Charpy specimens were cut out from the 40 mm cylinders in the pressing or axial direction, and in the radial direction. The electrical conductivity was measured in the 10 mm diameter die lined with zirconia. Cubic compacts for the dilatometry were compressed slightly in the compacting direction after ejecting from the die.<BR>The toughness of the specimens with their length in the radial direction increased with test temperature, while those in the pressing direction remained almost constant, leading to an increased anisotropy of the toughness.<BR>The electrical conductivity decreased more in the elctrolytic iron powder compacts than in the reducedore ones, and during the ejecting rather than during the unloading.<BR>Re-pressing green compacts led to a decreased anisotropy of the toughness and decreased axial shrinkage during the sintering.
社団法人粉体粉末冶金協会の論文