High-Temperature Synthesis of Al–Zr–W Aluminum-Matrix Alloys

Abstract

This paper reports the preparation of Al–Zr–W aluminum-matrix alloys containing reinforcing inclusions of various phases. The alloys have been produced by the aluminothermic reduction of starting mixtures consisting of zirconium and tungsten oxides in the first stage and of baddeleyite and scheelite mineral concentrates in a second stage. According to our experimental data, the use of baddeleyite and scheelite instead of zirconium and tungsten oxides in the starting mixture produces no significant changes in the elemental composition of the alloy: the total zirconium and tungsten content of the alloy is 31–32 wt %. Characterization of the alloy prepared using the mineral concentrates has shown that the aluminum matrix contains inclusions of the Al3Zr and Al4W intermetallic phases and a small amount of the ZrN nitride. The volume fraction of the inclusions in the alloy is 32–38%. Most of the structural constituents of the alloy contain a small amount of unwanted silicon and iron impurities (~3%), which originate from the mineral concentrates. In the future, to reduce the impurity concentration we plan to use technological approaches that will ensure preliminary purification of mineral concentrates.