Influence of the modifying ability of various compositions on the microstructure and properties of the AK7ch alloy

The results of experimental studies of the AK7ch Al-Si alloy before and after modifying with compositions-(i) the K2ZrF6 industrial modifier, (ii) modifying mixture based on refractory metal oxides and cryolite, and (iii) the Arsal 2120 foreign flux-are presented. It is established that modification of the AK7ch alloy leads to the uniform distribution of eutectics (alpha-Al + beta-Si) and structural components, diminishing silicon crystals by a factor of 1.5-2.0 on average, refining, and variation in shape of Fe-containing phases. It is shown that an increase in relative elongation by a factor of 2 and more is characteristics of all modified samples, and the tensile strength, hardness, and densities of casts for all the samples are different and have an ambiguous character.