( 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: 研究了機(jī)械合金化制備的納米晶W-xCu（x=15，20，25）復(fù)合粉末的燒結(jié)行為。 結(jié)果表明， 納米晶WCu復(fù)合粉末燒結(jié)致密化強(qiáng)烈地依賴于燒結(jié)溫度與燒結(jié)時(shí)間。 當(dāng)燒結(jié)溫度從1 150 ℃提高到1 200 ℃時(shí)， 燒結(jié)30 min后的燒結(jié)體相對(duì)密度由91％~94%增加到97％~98%；當(dāng)燒結(jié)溫度超過(guò)1 300 ℃時(shí)， 燒結(jié)體發(fā)生快速致密化， 5 min內(nèi)相對(duì)密度即可達(dá)到98%左右。研究還發(fā)現(xiàn)， W-Cu合金中W晶粒尺寸也強(qiáng)烈地依賴于燒結(jié)溫度，即燒結(jié)溫度愈高， W晶粒長(zhǎng)大愈顯著。 當(dāng)壓坯在1 200~1 250 ℃燒結(jié)30 min后， 所得到的晶粒度約為300~500 nm，其中經(jīng)1 200 ℃燒結(jié)時(shí)的晶粒尺寸約為300~350 nm。 另外， Cu含量增加有利于燒結(jié)致密化， 并降低W晶粒長(zhǎng)大的趨勢(shì)。
關(guān)鍵字: 納米W-Cu； 燒結(jié)致密化； 燒結(jié)
（ State Key Laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract: Sintering behavior of nanograined W-xCu(x=15, 20, 25) composite powder produced by mechanical alloying was studied. The results show that sintering densification of nanograined powder is largely dependent on sintering temperature and time. Relative density rises from 91%-94% to 97%-98% when sintering temperature increases from 1 150 ℃ to 1 200 ℃. When the sintering temperature is higher than 1 300 ℃, faster densification can be performed within shorter time, e.g. relative density can reach about 98% within 5 min. Likewise, W grain size is also greatly dependent on sintering temperature, so that W grain gradually coarsens with the increasing sintering temperature. The grain size of 300-500 nm can be achieved after sintering at 1 200-1 250 ℃ for 30min and the grain size is only about 300-350 nm at 1 200 ℃. In addition, the increasing Cu content is beneficial to further sintering densification and less grain growth.
Key words: nanograined W-Cu; sintering densification; sinter
