P/M materials from splat quenched flakes of 2219 aluminum alloy containing transition metals

Abstract

Rapidly solidified flakes of 2219 aluminum alloys containing transition metals were produced by atomizing the alloy melt and subsequent splat quenching onto a water-cooled copper single roll. Consolidation of these flakes was done by cold pressing, degassing and hot extrusion at a reduction ratio of 25 to 1. As splat-quenched flakes showed cellular structures, consisting of primary α phase and eutectic. The hardness of flakes and P/M materials increased with the addition of transition metals due to fine dispersion of their eutectic compounds. However, P/M materials with higher addition of transition metals showed much lower age hardening than 2219 alloy, and this was attributed to lower solid solubility of Cu due to formation of compounds between Cu and transition metals. Mn was most effective for strengthening 2219 alloy by the addition of transition metals. Tensile strength of T6 materials with 2wt% Mn addition was 476MPa, and that of F material with 6wt% Mn addition was 536MPa. Furthermore, Mn bearing materials showed appreciably higher fatigue strength than conventional 2219 alloy in torsional fatigue tests.