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本文通过光学显微分析、扫描电镜形貌照像、线扫描分析以及热分析液淬等手段研究了Te、P、Na等元素对高纯及工业纯过共晶、共晶Al-Si合金中初晶Si及共晶Si形貌及其结晶过程的影响,提出了Te在合金中使共晶Si相变质的机理的看法,认为:Te使工业纯Al-Si合金共晶Si相变质主要原因有二:(1)减弱或消除了工业纯Al-Si合金中微量磷的影响,使其结晶过程及共晶形貌及尺寸更接近于高纯合金;(2)过剩的Te原子一方面促使α(Al)初生晶的形核,并抑制其枝晶胞生长,促使α(Al)枝晶尺寸和二次枝间隙减小。另一方面,吸附于Si晶体侧面,抑制其侧向分枝,这与P促进初晶Si形核细化初晶Si和Na促使共晶Si生长方式改变而成长为纤维状的机理是不一样的。
In this paper, the effects of Te, P, Na and other elements on high purity and industrial pure hypereutectic, eutectic Al-Si alloys were studied by means of optical microscopy, scanning electron microscopy, line scanning and thermal analysis. Primary Si and eutectic Si topography and its crystallization process, put forward Te in the alloy eutectic Si metamorphic mechanism of view, that Te: industrial pure Al-Si alloy eutectic Si phase change the main reason There are two ways: (1) weakened or eliminated the influence of trace phosphorus in industrial pure Al-Si alloy, which makes the crystallization process and eutectic morphology and size closer to high purity alloy; (2) Excess Te atoms promote α (Al) primary crystal nucleation and inhibition of dendritic cell growth, prompting α (Al) dendrite size and secondary branch clearance decreased. On the other hand, adsorbed on the side of Si crystal and inhibited its lateral branching, which is not the same as the mechanism that P promotes the nucleation of primary Si and the primary Si and Na promote the growth of eutectic Si and grow into fibrous of.