| 摘要 |
PURPOSE:To obtain an ultra-heat resistant sintered alloy suitable for a cutting tool having a hard phase and a bonding phase, by compounding a composite carbonitride powder of Ti, W and Va group metal with an MgO powder and a W-powder while pressing the obtained composition to form a green compact which is, in turn, sintered at a high temp. CONSTITUTION:A green compact having a composition prepared by compounding 10-65% of a composite carbonitride solid solution powder of Ti, W and a Va group metal, 0.5-10% of an MgO powder and the remainder of a W-powder is sintered at a high temp. of 1,800-2,700 deg.C in a vacuum or inert gaseous atmosphere. During this sintering, MgO is reacted with the solid solution to reduce MgO and the C-content in the solid solution. By this method, an ultra-heat resistance sintered alloy having a hard phase forming component comprising 10- 65% of the composite carbonitride solid solution of Ti, W and the Va group metal and 0.01-1% of MgO and a bonding phase forming component comprising the remainder of W and inevitable impurities is obtained. This alloy has high toughness and high hardness and, if it is used as a hot processing tool, excellent properties thereof are developed.
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