REVIEW OF THE TECHNIQUES FOR THE EXTRACTION OF 2ND-PHASE PARTICLES FROM ALUMINUM-ALLOYS

This article briefly reviews the methods developed for extracting the second-phase particles from aluminum alloys. The chemical phenol extra ction technique has been compared with the electrochemical potassium i odide (KI)-in-methanol method for two heat-treatable 6000-series alloy s. It is demonstrated that by carrying out the centrifuging warm in th e phenol method, the technique can handle quite large sample sizes wit hout contamination and regardless of the heat-treated condition of the sample under examination. In contrast, the KI-in-methanol method is l imited to homogenized materials. The phenol particle extraction from h igh-Cu (<1.0%)-containing alloy showed contamination arising from the metallic Cu that appears to originate from the Cu in the matrix, rathe r than from Cu-containing second-phase-particles. (C) Elsevier Science Inc., 1996