【摘要】 本文以扫描电镜(带X射线波长谱仪和能谱仪)为主要工具,对一种Al-Si-Cu-Mg亚共晶铸造合金的Sr变质作了研究,观察到,合金中加Sr,并不改变Al-Si共晶团的尺寸,仅改变共晶Si的形貌,亦即加Sr不是通过影响共晶Si的成核,而是影响共晶Si的生长,以达到变质效果的,为解释所观察到的实验结果,本文还引入了“变质阈值”这一概念,并认为具有普遍意义。更多还原

【Abstract】 The Sr modification of an Al-Si-Cu-Mg hypoeutectic cast alloy has been investigated by using SEM with both wavelength and energy dispersive X-ray spectrometers. It is found that the Sr addition does not affect the size of Al-Si eutectic cells in the alloy, but changes the morphology of eutectic Si. Hence, the Sr modification is resulted not by the change in nucleation of eutectic Si, but by that in mode of its growth. An available new idea "modification threshold value" was also proposed.更多还原