Krzysztof Saja

Optimization of grain refinement and modification of the eutectic in hypo- and transeutectic Al-Si alloys

Abstract

The procedures of grain refinement and modification of a silicon eutectic in hypo- and transeutectic silumins belong to important factors shaping their microstructure as well as physico-mechanical and technological properties. Due to this fact, the study attempts to address a proper, optimal, selection of refining additions αAl - a solid solution as well as additions modifying the silicon eutectic (αAl + βSi), depending on the eutecticity degree of the Al-Si system. The melts were realized at the Department of Non-Ferrous Metal Alloys of the Foundry Research Institute in Kraków. according to the experiment schedule. The obtained results of the examinations of the mechanical properties (Rm, Rp0.2, A5, Z and HB) underwent statistical treatment. The results, based on elaborate graphic interpretation, enable an easy selection of the amount of refiner (Ti5B1) and modifier of the eutectic silicon (AlSr10), depending on the silicon content (at wt. %) in the Al-Si system.


Keywords: Al-Si alloys, grain refinement, eutectic modification, mechanical properties,
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