( 中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室， 長(zhǎng)沙 410083)
摘 要: 采用機(jī)械合金化（MA）制備了晶粒尺寸為8~18 nm的90W-7Ni-3Fe納米晶粉末（MA粉末）。 將粉末注射成形， 在1 480~1 500 ℃經(jīng)3~5 min瞬時(shí)液相燒結(jié)。 結(jié)果表明， 采用瞬時(shí)液相強(qiáng)化燒結(jié)可以得到W晶粒為3~8 μm近全致密的細(xì)晶鎢合金， 顯微組織為細(xì)小的球形W晶粒均勻地連續(xù)分布在纖維狀粘結(jié)相中， 燒結(jié)坯具有好的拉抻性能。 長(zhǎng)時(shí)間的傳統(tǒng)液相燒結(jié)使球狀W晶粒迅速粗化， 而且密度和強(qiáng)度下降， 但延伸率反而增加。 在MA粉末中添加微量Y2O3后采用瞬時(shí)液相燒結(jié)， 可以使合金抗拉強(qiáng)度提高到1 055 MPa， 延伸率提高到16.5%。
關(guān)鍵字: 瞬時(shí)液相燒結(jié)； 90W-7Ni-3Fe納米晶粉末； 機(jī)械合金化；注射成形
中圖分類(lèi)號(hào): 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
