GB1268549A - Improvements in and relating to dispersion-hardened metals and alloys, and articles made therefrom - Google Patents

Abstract

1,268,549. Producing dispersion-hardened alloys. DELTA METAL (B.W.) Ltd. May 29, 1970 [June 5, 1969], No.28489/69. Heading C7D. A dispersion-hardened metal or alloy is produced by a method including the step of melting particles of the metal or alloy (or a reducible compound thereof) which is to constitute the matrix of the finished product, after the particles have been coated with a compound, whereby particles of dispersoid formed from the latter compound become diffused or dissolved in the matrix material, then solidifying. The solidified particles may be coated with a further charge of the compound forming the dispersoid and remelted and again solidified, the operation being repeated as desired to increase the proportion of dispersoid. The initial matrix material may be a powder comprising one or more reducible oxides of one or more of the metals: Cu, Ni, Fe, Mo, Co, or alloys thereof; the compound forming the dispersoid may be MgO, Al 2 O 3 , CaO, TiO 2 , ZrO 2 , ThO 2 and/or rare earth metal oxides. The melting may be carried out in a furnace, or by carrying the particles entrained in air or oxygen into a flame from a flame (e.g. oxyacetylene) or plasma gun. The melted particles may be rapidly cooled by quenching in water or an inert gas stream. Where the matrix material comprises oxide particles, the cooled particles may be heated in a reducing gas e.g. H 2 , in batches in a furnace, or continuously by falling through successive perforated floors in an enclosure. The reduced particles may be consolidated or compacted into billets by powder metallurgy. For forming a dispersion of MgO in Cu, CuO powder is dampened by a suspension of MgO in water, or a solution of a Mg compound decomposable to the oxide by heating the mixture in a fluidized bed, e.g. Mg methoxide dissolved in methyl alcohol, and the solvent evaporated leaving CuO particles coated with MgO, prior to reduction.