GB700607A - Improvements in or relating to the manufacture of alloys - Google Patents

Abstract

A process for the manufacture of an alloy consisting of two or more metals comprises the steps of pressing a metal powder or a mixture of two or more metal powders to form a compact and, while the pressed compact is contained in a confined space, heating it in contact with the vapour or vapours of one or more volatile metals or volatile metallic compounds and sintering the product. The volatile metal may be added from a material or mixture capable of generating under the action of heat a suitable quantity of the desired vapour, the subsequent sintering also being carried out in the container. This material or mixture may be in powder form, e.g. as a second pressed compact with or without a refractory diluent, e.g. of a metal the melting point of which is higher than the sintering temperature to be employed. The source of the volatile metal may be a master alloy of the said metal with the base metal of the alloy to be produced, the composition of the master alloy being that of an intermetallic compound of melting point below the sintering temperature employed in the process. The metal or metals of the first pressed compact are preferably non-volatile and may be mixed with a small amount of refractory oxide and/or a small proportion of readily vapourizable substance which is completely vapourized on heating. This compact may be formed under a pressure up to 20 tons per sq. in. and it may then be degassed before the heating. The container, which may be an iron or steel tube, may have a slight leak and is evacuated prior to heating, the heating then taking place in an evacuated furnace chamber, the vacuum in which is maintained throughout heating and sintering. The alloy produced may consist substantially of an a solid solution phase, e.g. of a Ni-Mg alloy. Non-volatile metals may be introduced into the compact by means of a material or mixture comprising the said metal and either a volatile compound of the said metal or a substance which reacts with the metal to form a volatile compound. Thus an Al-Ni alloy may be made by introducing Al into an Ni compact in the form of an Al halide. Specifications 580,774 and 700,605 are referred to.