Determining the diffusion coefficient in simultaneous saturation with boron and carbon of austenite alloyed with cooper in powder metallurgy structural materials
Ivan Mitev
Abstract
In many of the cases machine parts obtained by powder metallurgy with high mechanical characteristics when operating in aggressive environments must possess high durability and corrosion resistance. It requires them to be complex alloy, which in turn hinders technological operations related to their production - pressing, sintering. In this regard in recent years there is increased scientific interest in the processes related to multi-surface diffusion enrichment of such details, whose matrix is made up mostly of iron-carbon powdered alloys and supplements - copper, phosphorus, tin, etc., facilitating technology development. In this development with a view to intensify the diffusion processes of boroncarburizing powder metallurgy workpieces of the system Fe-C-Cu defined values for the activation energy - Q, the exponential factor - D0 and the diffusion coefficient - D. Of the study were subjected to powder samples of iron powders ASC 100.29 type, to which was added 0.1% carbon and 1,0÷3,0% copper. Monitored the influence of the amount of copper in the samples, their density and temperature of boroncarburizing on Q, Do and D. Expressions are presented for determining the diffusion coefficient in the simultaneous saturation with elemental boron and elemental carbon in austenite alloyed with copper, depending on the density of the samples and the copper content in them