Effect of Heating Rate on the Formation of Intermetallics during SHS Process

Self-propagating high-temperature synthesis is a simple and efficient method for the synthesis of various compounds including ceramics and intermetallics. In this process, the compressed mixture of elemental or master alloy powders is ignited or heated to initiate the exothermic reactions leading to the formation of desired compounds. In order to control the process efficiently, the effect of several important parameters has to be determined in each applied alloy system. Previous results showed that those parameters are: initiation temperature, process duration, pressure used for compression and heating rate. This paper is devoted to the description and explanation of the effect of the heating rate on the formation of intermetallics during self-propagating high-temperature synthesis in Fe-Al and Ni-Ti systems. Differential thermal analysis of compressed powder mixtures under various heating conditions and microstructure observation of samples prepared by various heating rates using electric resistance heating and spark plasma sintering were carried out. The effect of heating rates on the formations of intermetallics in studied systems is discussed in this paper