Some features of the densification of a P/M material during hot forging with elements of extrusion
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In the hot re-pressing of porous P/M preforms with elements of direct and reverse extrusion, in the initial stage work is expended mainly in the densification of the P/M material and then, after this has been completed, in extrusion. Initially, extrusion may take place both with and without the P/M material experiencing a loss of density. The probability of loss of density increases on passing from static to shock loading and from direct to reverse extrusion, and also with increasing D/d ratio. In the range of phase transformation temperatures stepwise reductions in the density of the material of the extruded element and its length are observed. The density of the bulk of the specimen is sensitive to temperature changes only at W < Wmax.
KeywordsTemperature Change Phase Transformation Transformation Temperature Density Increase Shock Loading
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