Structure, Phase Composition and Properties of Al3Er Master Alloys Obtained by “Hydride Technology” and Mechanical Treatment

Abstract

The incorporation of rare-earth metals beneficially influences the microstructure, mechanical properties, and overall performance of base alloys by forming modifying and strengthening intermetallic phases. This investigation focuses on the production of Al₃Er master alloy using “hydride technology,” involving the preliminary hydrogenation of erbium and mechanical processing of starting components. The study demonstrates the impact of pre-mechanical treatment of an Al–Er powder mixture on the structure and properties of Al₃Er master alloy. The master alloy obtained with pre-mechanical processing exhibits a homogeneous structure comprising an aluminium matrix with evenly dispersed Al₃Er inclusions. Thin interlayers of dispersed eutectics, enriched with approximately 20–25 wt % erbium, are observed along the boundaries of the Al solid solution. Structural analysis of Al₃Er master alloy using the Rietveld method revealed two metallic phases: aluminium solid solutions (~95.14%) and the intermetallic compound Al₃Er (~4.86%). With machining, the average Vickers microhardness value of regions predominantly composed of Al₃Er was (92.4 ± 8.0) HV, reaching a maximum of (105 ± 8.0) HV. In contrast, the average microhardness value of the master alloy obtained without machining in these areas was (68.4 ± 8.0) HV.