Vanadium Edition Influence on the Structural and Phase Parameters of Al–Si–Cu Alloys

Processy litʹâ, 2019, Tom 138, №6, p.52-58

Abstract

Received 17.10.2019

UDC 669.71.782.3.292

The effect of vanadium addition on the structural and phase parameters of Al−Si−Cu cast alloys under different crystallization conditions is considered. A non-serial hyper-eutectic Al−14Si−4Cu alloy was chosen for experiments. Such composition made it possible to simultaneously evaluate the effect on such structural parameters as aluminum-based solid solution, primary silicon crystals and eutectic.After modification and crystallization in graphite mold, more homogeneous and less contrasting structure is observed, respectively to the constituent parts distribution. The eutectic is distributed more evenly, and primary silicon crystals are not recognizable. Solid solution alloying grade rising is significantly noted. Al matrix includes 1.2 wt.% Si, 2.36 wt.% Cu, and 0.85 wt.% V compare to non-modified alloy with 0.77 wt.% Si and 0.2 wt.% Cu. Moreover, it is obvious that vanadium promotes the clusters formation of iron-rich phases, which have a very favorable, non-needle morphology, but they are majorly deposited near to Cu-rich conglomerates. During accelerated crystallization of the modified melt, a similar, but slightly enhanced effect is observed: the structural components are dispersed even more significantly, and the Al-based solid solution has even higher alloying rate: 1.59 wt.% Si, 2.82 wt.% Cu, and 1.17 wt% V. Also, Al + Si eutectic becomes even smaller and less-contrasted. However, the Cu-rich and Fe-rich phases in the eutectic areas are not distributed more uniformly. In that case, Iron-rich phases also have a very favorable, non-needle morphology. They mainly situated separately from Cu-rich conglomerates, instead of previous example.