Some Characteristics of Hot-Extruded Powder Metal Billets
Many alloys are difficult to manipulate by the hot-working of a cast ingot because the cast structure contains segregated areas of hard, brittle phases. The breakdown of such a cast structure into a uniform distribution of phases involves a lengthy and careful thermal working cycle. It is suggested this problem might be overcome and superior structures obtained by the consolidation of atomized prealloyed powders; such powders are necessarily free of macro-segregation. Hot extrusion of a compacted billet is confirmed as a valid technique. This paper describes experiments undertaken to assess the feasibility of the process. Initially, simple metals and alloys were investigated with a view to determining the extrusion parameters and the general quality of the extruded product. Later, more difficult materials were investigated. The properties of a number of materials extruded from powders are given. It is shown that a very fine and uniform distribution of phases can be obtained by this method, which in some cases gives superior properties.
KeywordsCalcium Hydride Atomize Powder Total Oxygen Content Prealloyed Powder Superior Structure
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