摘要
研究添加0.1%-2.0%Ba（质量分数,下同）对高Si原位自生Mg2Si/Mg-Zn-Si复合材料组织和力学性能的影响。结果表明：随着Ba含量的增加,初生Mg2Si由树枝晶转变为多面体颗粒,其尺寸先减小后增大;汉字状共晶Mg2Si也先减少后增加;复合材料的力学性能显著改善。当Ba含量为1.0%时,其细化变质效果最好,合金的综合力学性能最佳,这是由于Ba的加入形成了大量细微的BaMg2Si2粒子可作为初生Mg2Si的异质形核核心,从而细化变质了Mg2Si;当Ba含量过高（〉1.0%）,BaMg2Si2相聚集长大导致了过变质现象,力学性能下降。变质为细小多边形的Mg2Si颗粒减少了加载时应力集中与裂纹产生、扩展;其弥散分布阻碍了变形时位错运动,因此强化了复合材料。
Effects of 0.1%-2.0%（mass fraction） Ba addition on the microstructure and tensile properties of Mg2Si /Mg-Zn-Si composites with high Si content were investigated.The results indicate that,the morphology of primary Mg2Si in the composites changes from large dendrite to fine polygonal with the increasing Ba content,and its average size sharply decreases until addition of Ba 1.0% and then slowly increases.The average size of eutectic Mg2Si also shows the same change trend.Numerous tiny BaMg2Si2 particles act as the heterogeneous nucleation substrate for primary Mg2Si.It is also found that BaMg2Si2 size in Mg2Si is obviously coarsened as addition of Ba surpasses 1.0%,which is responsible for over modification.Refined Mg2Si particles dispersion-strengthen the composite and results in the improvement of ductility.The proper Ba content is a key factor to obtain effectively refined Mg2Si and enhanced composite.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2010年第4期63-68,共6页
Journal of Materials Engineering
基金
陕西理工学院专项科研基金资助项目(SLGQD0746)
关键词
BA
MG2SI
变质
异质形核
Ba addition
Mg2Si
modification
heterogeneous nucleation
