Al-Al₄C₃细化剂和超声场对纯Mg组织的影响

来源期刊：金属学报2010年第12期

论文作者：高声远 乐启炽 张志强 崔建忠

文章页码：1495 - 1500

关键词：超声场； 纯Mg； Al₄C₃； 晶粒细化

Key words：ultrasound field； pure Mg； AI₄C₃； grain refinement

摘    要：在不同Al-Al₄C₃细化剂添加量条件下,对纯Mg熔体进行孕育处理.当添加质量分数为1.0%Al Al₄C₃细化剂时细化效果最佳,α-Mg晶粒平均尺寸由毫米级降至106μm.在纯Mg熔体中施加不同功率超声场,当施振功率为600 W时细化效果最好.研究表明,空化泡破碎产生的过冷对形核具有促进作用,空化泡的破裂及声流对熔体的搅动使得细小枝晶破碎,形成新的结晶核心,这一过程对形核起主要作用.功率超声与Al-Al₄C₃细化剂共同作用于纯Mg熔体过程,可以显著细化晶粒.其机理为超声对杂质的"活化"作用.

Abstract: The melt of pure Mg was inoculated at the conditions of different addition amounts of Al-Al₄C₃ refiner.When adding 1.0%Al-Al₄C₃ refiner,the refining effect is the best and the average grain size of α-Mg is reduced from millimeter level to 106μm.Ultrasound fields with different power levels were applied on the melt of pure magnesium and the best refining effect was obtained when the power was 600 W.The results show that the undercooling formed by breakdown of cavitation bubbles may have a promoting effect to nucleate.The breakdown of cavitation bubbles and the agitations of acoustic stream on the melt cause the fragmentation of fine dendritic crystal which could form new crystallization nuclei,this process plays the main role for nucleating in the melt.The combined application of ultrasound and Al-Al₄C₃ refiner to the melt of pure Mg could significantly refine its grain.The mechanism would be an the activation effect of ultrasound on the impurities in the melt.