( 中南大学 粉末冶金国家重点实验室， 长沙 410083)
摘 要: 采用机械合金化（MA）制备了晶粒尺寸为8~18 nm的90W-7Ni-3Fe纳米晶粉末（MA粉末）。 将粉末注射成形， 在1 480~1 500 ℃经3~5 min瞬时液相烧结。 结果表明， 采用瞬时液相强化烧结可以得到W晶粒为3~8 μm近全致密的细晶钨合金， 显微组织为细小的球形W晶粒均匀地连续分布在纤维状粘结相中， 烧结坯具有好的拉抻性能。 长时间的传统液相烧结使球状W晶粒迅速粗化， 而且密度和强度下降， 但延伸率反而增加。 在MA粉末中添加微量Y2O3后采用瞬时液相烧结， 可以使合金抗拉强度提高到1 055 MPa， 延伸率提高到16.5%。
关键字: 瞬时液相烧结； 90W-7Ni-3Fe纳米晶粉末； 机械合金化；注射成形
中图分类号: TF 123
（ State key laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract: Nanostructured 90W-7Ni-3Fe powders(MA powders) with tungsten crystalline size of 8-18 nm were prepared by mechanical alloying (MA).The powders were mixed with an organic polymer binder, then injected and debinded. After that, the brown compact was consolidated via transient liquid phase sintering at 1 480-1 500 ℃ for 3-5 min. The mechanical properties and microstructure of the sintered alloy were studied. At same time, the brown compact was consolidated via traditional liquid phase sintering at the same temperature for 120 min for comparison. The results show that transient liquid phase sintering helps to obtain fully dense, fine spherical grained tungsten alloy with good tensile strength and elongation; the size of tungsten grains is 3-8 μm; the alloy has typical liquid phase sintering microstructure， the fine spherical tungsten grains uniformly imbed in the continuous fiber binder phase; long time traditional liquid phase sintering coarsens the tungsten grain rapidly, and makes the density and tensile strength decrease except that elongation increases. Minor addition of Y2O3 in MA powders improves the tensile strength (1 055 MPa) and elongation (16.5%) of the tungsten alloy via transient liquid phase sintering.
Key words: transient liquid phase sintering; nanostructured W-Ni-Fe powder; mechanical alloy; injection molding
