Self-Propagating High-Temperature Synthesis: Non-Equilibrium Processes and Equilibrium Products

Abstract

The nature of SHS process was studied, and conditions under which equilibrium and non-equilibrium regimes take place for wave propagation and structure formation of SHS products are under consideration. The important role of cooling down time is shown. Depending on its magnitude, either autoannealing or autoquenching processes can take place in the products after combustion front propagation. The correlation between transition from non-equilibrium to equilibrium state of the product with prolongation of cooling time was examined as well as character of products and processes was indicated in dependence on relationship between the characteristic times of combustion, time of cooling down, and structure formation in SHS product.

Comparative Investigation of the Structure, Phase Composition, and Mechanical Properties of Ni-Based High-Temperature Alloys Manufactured by Different Methods

“…Owing to the consistent trend to the increase in the cost of energy source materials and initial components of heat-resistant nickel-based alloys, energy and resource saving technologies for the fabrication of such materials are currently being developed. Selfpropagating high-temperature synthesis (SHS) is one of the promising methods for the design of new hightemperature metal and ceramic materials [11,12]. In this work, the method for the fabrication of cast materials in the combustion mode, which was referred to as the SHS technology of high-temperature melts [13] or SHS metallurgy [14][15][16], was used for the fabrication of Ni-Cr-W alloy.…”

“…At this temperature, the target product (metal melt) and the slag phase (metal oxide reducing agent) exist in the liquid phase and there is a gravitational separation (delayering) of the liquid metal and slag melts under the force of gravity. The ingots of cast high-melting compounds [12,17], solid alloys, oxide and composition materials [18,19], and also their weldings [20] are formed after cooling depending on the composition of the mixture and the conditions of synthesis.…”