摘要
研究了硼对AZ91镁合金显微组织和硬度的影响。结果表明:当B的加入量小于0.01%(质量分数)时,随硼加入量的增加,合金铸态组织和平均晶粒尺寸显著减小,布氏硬度明显提高;B加入量为0.01%时,合金平均晶粒尺寸由未加B的120μm细化到30μm左右;当加入量超过0.01%时,晶粒有粗化的趋势;分析认为具有密排六方结构的高熔点化合物AlB2(Tm=980℃)可作为α-Mg的异质核心,大量异质结晶核心的存在是使-αMg晶粒细化的主要原因。
The effects of boron on microstructure and mechanical property of AZ91 alloy were investigated. The results show that the microstructure and average grain size of as-cast alloy is remarkably refined, and hardness （HB） is remarkably increased with the increase of B content when the content of B addition is less than 0.01%（mass fraction）. The average grain size is decreased to 30 pan from 120 pan when B content is 0.01% .The grain size is increased when B contcnt is more than 0.01%. It is concluded that high melting point compounds AlB2 （Tm=980℃） with HCP crystal structure can serve as the nucleating sites of α-Mg .Lots of the nucleating sites are the main reason which make α-Mg grain fine.
出处
《热加工工艺》
CSCD
北大核心
2006年第24期28-30,共3页
Hot Working Technology
关键词
AZ91镁合金
硼
细化变质
显微组织
硬度
AZ91 magnesium alloy
boron
grain refinement
microstructure
hardness
