GB842226A - Improvements in or relating to methods of producing malleable bodies of metallic beryllium - Google Patents

Abstract

842,226. Powder metallurgy. BRUSH BERYLLIUM CO. Oct. 21, 1957, No. 32845/57. Class 82(1) Malleable bodies are made from beryllium by charging the powdered metal into a container or die (13), subjecting the interior of the container and the beryllium to a preliminary evacuation and heating at a temperature below sintering temperature until a large part of any gas or vapour sorbed in the powder has been removed, .then subjecting the interior of the container and the beryllium to a prolonged combined evacuation of gases and heating at a higher temperature ranging from that at which sintering begins upwards to a temperature below that at which pronounced grain growth of the beryllium would occur, until the beryllium is sintered throughout, and simultaneously applying mechanical pressure (at 17). A suitable vacuum is 10 microns or less of mercury; suitable temperatures are 900‹C (preliminary) and 1000‹ to 1125‹C for sintering; the mechanical pressure may be only 68-70 1b./sq. inch. Purified beryllium powder is carefully weighed and according to the density (say 1.85) required for a body of known volume, placed in a removable stainless steel liner in container 13, and the vacuum pump is connected at 12 to reduce the interior pressure to 10 microns or less the plunger 16 being lowered in the position shown. The furnace heated by burners 5 then heats the berlyllium &c. to 900‹C, the vacuum pump still acting. Plunger 16, is then depressed to exert a moderate pressure of some 68-70 1b./sq. inch upon the beryllium and simultaneously the heating is increased to between 1000‹C and 1125‹C to sinter it, the pump still evacuating at 12. When the volume indicator gauge 28 shows the computed volume to have been attained, the heating is cut off and the plunger raised. When cool, the furnace is opened, the liner 15 removed and the liner peeled from the body. Fig. 2 shows stainless steel die parts 33, 34 as used in making a beryllium spur gear wheel.