ANALYSIS OF THE THIXOEXTRUSION OF Al-4,5wtCu ALLOY

摘要

This work analyses the formability of Al-4,5wt%Cu alloys in the semi-solid state, by extrusion (thixoextrusion process). Semi-solid rheocast material, produced by controlled partial melting of ultra-refined structures, was submitted to direct extrusion tests in a specially developed apparatus. Forming forces were monitored during the processes, as a function of processing time. Processing parameters analysed were volume fraction of solid (billet temperatures of 617 and 625°C), and extrusion ratio (Re varying from 40 to 90%). Results were as follows: good formability for all conditions, equiaxial and fine macrostructure, microstructure containing globular cc-phase with no residual stress. Results also showed that forces required in semi-solid extrusion can be significantly lower than in fully solid.