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Nonlinear mechanisms of interaction and regularities of reaction sintering of disperse-strengthened metal alloys


Work number - M 27 FILED

Presented Frantsevich Institute for Problems of Materials Science, NAS of Ukraine

Authors:
Ph.D. Petrash K.M.

The scientific work is devoted to solving an important scientific and technical problem of establishing the regularity of the reaction sintering of metal compositions that contain non-interacting compounds, and the development of heat-resisting dispersion-hardened nichrome and the technology of obtaining products of them.

For the first time, thermokinetic models of irreversible processes initiated by contact melting of components based on theoretical analysis taking into account collective interactions in the Ni-Al and Ti-Al reaction systems of and the representation of the flow reactor were constructed. Different kinds of thermokinetic trajectories of interaction process development were established.

The experimental thermokinetics of reacting systems (Ni-Al, Ti-Al, Ni-Ti, Ni-Sn, Cu-Ti, Cu-Sn), which are the basis of industrial alloys were studied.

It has been found that samples of almost all investigated powder double systems with a relative density of more than 80% give a significant increase in volume during the sintering process. However, the introduction of a certain amount of chemically inert impurities localizes the reaction processes throughout the volume of the presses and prevents small pores from being coagulated into cavities. This contributes to the slowing of the growth of the raw powder blanks and, eventually, leads to significant shrinkage. Small pores in each small local volume take part in the mass transfer and activate the shrinkage process in the late stages of sintering.

Heat-resistant dispersion-hardened alloys based on nichrome with an aluminum content of up to 6% and yttrium oxide (Y2O3) up to 1,5% were developed using reaction sintering, as well as developed technologies for producing products from them, in particular, the modes of rolling thick billets and thin sheets with a thickness of up to 0.1 mm. Solder compositions and thermo-reaction soldering conditions for thick blanks were developed, which are used in the manufacture of the air intake of a hypersonic aircraft. Soldering regimes and other technological operations for the manufacture of heat-protective panels for hypersonic and reusable spacecraft were also worked out.

The obtained physical-mechanical and functional properties of dispersion-strengthened nichromes provide in aggregate the necessary performance of reusable space systems at the temperatures up to 1200 0C.

Number of publications: 19 articles (2 - in English-language journals with an impact factor). The total number of references to the author's publications / h index of work, according to the databases is respectively: Web of Science - 0/0, Scopus - 1/1, Google Shcolar - 16/2. Received 1 patent of Ukraine.

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