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用金相方法以及合金全腐蚀分离出Si相,分级沉降,然后进行扫描电镜观察的方法,对Al-Si合金未变质,Na,Sr,La变质的Si相进行了观察。发现La变质Si枝条最短,有时呈根瘤状,Na变质Si最长,Sr次之,此现象与变质剂的价电荷有关。在对上述退火试样观察中发现共晶Si相普遍溶解,再结晶产生新的Si晶。其中以La变质Si的再结晶速度最快,依次为Sr变质,Na变质,未变质的Si晶。对过共晶Al-Si合金考查结果表明,初晶Si并无溶解再结晶现象。再结晶速度与Si晶的平衡状态有关。据此提出“不平衡度”概念作为衡量变质结构的准则。
The phase of Si was separated by gravimetric method and total corroded alloy, and then graded and settled. Then the scanning electron microscopy was used to observe the unmetamorphic, Na, Sr, La metamorphic Si phase of Al-Si alloy. It was found that La metamorphic Si shoots were the shortest, sometimes nodular, Na was the longest and Sr was the second, which was related to the valence charge of the modifier. During the observation of the annealed sample, it was found that the eutectic Si phase was generally dissolved and recrystallized to produce new Si crystals. Among them, the recrystallization rate of La metamorphic Si is the fastest, followed by Sr metamorphic, Na metamorphic and unmodified Si crystal. The results of the hypereutectic Al-Si alloy showed that the primary Si did not dissolve and recrystallize. The recrystallization rate is related to the equilibrium state of Si crystal. Accordingly, the concept of “unbalance degree” is put forward as a criterion for measuring metamorphic structure.