STUDIES ON THE EFFECT OF MISCHMETAL ADDITIONS TO THE CAST AI-7Si-0.3Mg ALLOY AND ITS STRUCTURE PROPERTY CORRELATIONS

摘要

This paper deals with the effect of mischmetal(MM) addition on the microstructure, electrical conductivity, mechanical properties and fracture behaviour of the AI-7Si-0.3Mg alloy and also the alloys containing iron content upto 0.6%. Addition of 1% mischmetal was found to refine the structure (reduce the DAS) and modify the eutectic silicon. Lanthanum and cerium present in the mischmetal react with the other alloying elements to form fine intermetallic compounds like AlCe and other non-stoichiometric compounds thus contributing to the higher mechanical properties of the alloys containing iron content upto 0.6% in the room temperature as well as at elevated temperature(upto 473 K).