| 摘要 |
PURPOSE:To additionally improve ductility of an alloy by varying the characteristics of the outside part and core part of the alloy at the time of increasing the specific gravity of the W alloy contg. Ni and iron as a binder and sintering the same in gaseous H2 flow then heating and quickly cooling the alloy in a vacuum. CONSTITUTION:The outside part is composed of a powder mixture consisting of 93-97% W powder and the balance Ni and Fe and the core part of the powder mixture consisting of 85-91% W powder and the balance Ni and Fe. After such powder mixtures are packed into a molding tool without mixing, the powder mixtures are compacted under a hydrostatic pressure of 1-4ton/cm<2>. The resultant green compact is subjected to liquid phase sintering in the gaseous H2 flow of 0--60 deg.C dew point. The sintered body is subjected to a heat treat ment involving heating in a vacuum, then quick cooling. The two-layered W alloy having the higher ductility in the core part than in the outside part is thus obtd.
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