摘要
Sb的变质机理可分为影响形核理论与限制生长理论。影响形核理论又分为增加形核核心及减少形核核心二种假说。限制生长理论包括Sb降低Si的扩散能力假说、共晶Si被共晶Al超越假说、AlSb分子的吸附阻碍共晶Si生长假说、Sb质点阻碍共晶Si生长假说、Sb在固液界面富集假说、Sb吸附在共晶Si的表面阻碍共晶Si生长假说等。Sb变质的Al-Si合金共晶反应倾向于以体积凝固的方式进行。AlSb及Mg3Sb2是共晶形核的可能核心。Sb会降低Al-Si合金的共晶反应温度。纯Sb变质有50 min孕育期。Mg对Sb的变质有干扰作用。Sb的含量较高时会出现过变质现象。
Modification mechanism of AI-Si alloys by antimony can be classified as two kinds： nucleation hypothesis and growth hypothesis. The nucleation hypothesis includes nuclei increment theory and nuclei decrease theory. The growth hypothesis includes theory of Sb decreasing the confusion ability of silicon atom, theory of eutectic aluminum leading eutectic silicon, theory of adsorption of AISb on eutectic silicon, theory of restriction of pure antimony particles, theory of antimony atom enrichment in front of interface, theory of absorption of antimony atoms on eutectic silicon surface. The eutectic reaction of AI-Si alloys modified by antimony is apt to solid in a mushy mode. AISb and Mg3Sb2 are possible nucleus of eutectic silicon. Antimony modification can decrease the eutectic growth temperature of AI-Si alloys. Modification by pure antimony needs about 50 min. to attain a good result. Mg can neutralize the effects of antimony. Over-modification will occur if content of antimony is too high.
出处
《铸造》
CAS
CSCD
北大核心
2008年第3期211-214,共4页
Foundry
基金
江苏省自然科学基金(BK2004069)
