摘要
研究了在不同温度条件下钇在AZ91D镁合金熔体中的溶解情况。试验结果表明,当试验温度为750℃时,熔体中Y含量增加缓慢。通过分析不同时刻未熔金属块内部微观组织形貌发现,有大量Y原子与Al原子在溶解过程中结合成Al-Y原子团。这些原子团聚集在未熔的金属Y周围,并随着保温时间的延长而不断增长。部分Al-Y原子团在重力作用下沉降到熔液底部,形成Y的偏聚。当试验温度为850℃时,体积较大的Al-Y原子团无法稳定存在,大量体积较小的原子团弥散分布在合金熔液中,从而没有出现偏聚现象。另外,随着温度的升高,Y原子的扩散速度以指数倍数增长,使得850℃合金熔液中的Y元素增加速度比750℃从3.50×10-3%/min增加到3.55×10-2%/min。
The solution of yttrium in the AZ91D molten bath was studied at different temperatures. The experimental results showed that Y content in the solution increased slowly at 750 ℃. Microstructures of the unmelted alloy balk were analyzed in different samples. The results indicated that a number of Y atoms combined with Al atoms to form Al-Y atomic groups during Y dissolving and these atomic groups aggregated near the un-mehed Y metals. With holding time enlarging , a number of the atomic groups grew up and some of them dropped down and fell to the bottom of the molten bath by gravity. And so segregation of Y element happened. As the temperature was 850 ℃, it was difficult for Y and Al to form stable large atomic groups. A great number of small Al-Y atomic groups were dispersed in the molten bath. With the increase of the temperature, the diffusion rate of Y atoms showed exponential increase. Therefore, Y element content in the molten bath rose more quickly.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2008年第6期689-693,共5页
Chinese Journal of Rare Metals
基金
国家“十一五”科技支撑计划资助项目(2006BAE04B01,2006BAE04B04)
