顯微組織的影響
(中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 采用噴霧干燥−熱還原的方法制備納米級93W-4.9Ni-2.1Fe復(fù)合粉末和微量稀土摻雜的復(fù)合粉末，研究微量稀土摻雜對燒結(jié)致密化和晶粒尺寸的影響。結(jié)果表明：微量稀土摻雜能有效地降低該復(fù)合粉末的晶粒尺寸，并能改善粉末的分散度；納米級復(fù)合粉末在1 380~1 410 ℃液相燒結(jié)可實現(xiàn)材料的近全致密化，比同種成分的傳統(tǒng)鎢合金的燒結(jié)溫度降低了120 ℃左右，合金的相對密度可達99%以上；但微量稀土摻雜對燒結(jié)的致密化有一定的抑制作用；同時微量稀土元素對合金的晶粒尺寸的抑制作用主要發(fā)生在液相燒結(jié)階段。
關(guān)鍵字: 鎢合金；W-Ni-Fe復(fù)合粉末；Y2O3摻雜；燒結(jié)行為；顯微組織
fine-grain W-Ni-Fe powders
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract: Nano-grained W-Ni-Fe composite powders and Y2O3 doped W-Ni-Fe composite powders were fabricated by spray drying and subsequent thermal reduction process. The influence of trace Y2O3 on the sintering behavior of Y2O3 doped W-Ni-Fe composite powders was investigated. The results show that trace rare earth addition can reduce the crystalline size proficiently; The near full densification can be realized in the temperature range from 1 380 ℃ to 1 410 ℃, which is 120 ℃ lower than the temperature of sintered traditional tungsten heavy alloys. The relative density can achieve 99%, and trace rare earth element restrains the growth of tungsten grain, which happens mainly at the liquid phase sintering.
Key words: tungsten heavy alloy; W-Ni-Fe composite powder; Y2O3 doped; sintering behavior; microstructure
