ALLOY FORMATION PROCESS IN POWDER MIXTURES UNDER HIGH SPEED PLASTIC DEFORMATION

摘要

The use of traditional methods of powder metallurgy including sintering and long-term homogenizing does not permit to obtain bars with sufficient plasticity because of the presence of molten fragile phase appearing on the particle boundaries in the process of long term sintering. The main idea of this work is to get the homogeneous Ni-Mo alloys owing to the effect of superhigh-speed diffusion which appears by the optimum modes of hot deformation of heterocomponent powder mixture. In this case the process of alloy formation runs in a short interval of time due to tie nigh activity of dispersed powder components and mechanical activation of the mass transfer process. The investigations showed that in the Ni-Mo powder system this mechanism can be realized under deformation temperature 1450K. We have obtained almost homogeneous alloys with the solid solution structure from Ni-30 percent Mo powder mixture. Previous sintering during which the processes of diffusion homogenization start results in considerable deceleration of homogenization in the course of following deformation.