( 中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 研究了机械合金化制备的纳米晶W-xCu（x=15，20，25）复合粉末的烧结行为。 结果表明， 纳米晶WCu复合粉末烧结致密化强烈地依赖于烧结温度与烧结时间。 当烧结温度从1 150 ℃提高到1 200 ℃时， 烧结30 min后的烧结体相对密度由91％~94%增加到97％~98%；当烧结温度超过1 300 ℃时， 烧结体发生快速致密化， 5 min内相对密度即可达到98%左右。研究还发现， W-Cu合金中W晶粒尺寸也强烈地依赖于烧结温度，即烧结温度愈高， W晶粒长大愈显著。 当压坯在1 200~1 250 ℃烧结30 min后， 所得到的晶粒度约为300~500 nm，其中经1 200 ℃烧结时的晶粒尺寸约为300~350 nm。 另外， Cu含量增加有利于烧结致密化， 并降低W晶粒长大的趋势。
关键字: 纳米W-Cu； 烧结致密化； 烧结
（ 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
