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This work aims to optimize the parameters of the SHS process for the preparation of NiTi shape memory alloy to obtain a high-purity, low-porosity material. For this purpose, high heating rate (over 300 °C min−1), temperature of 1100 °C and process duration of 20 min were determined as the optimal parameters. To prevent nickel depletion of the product and to minimize the porosity, the use of coarse titanium particles (200–600 μm) with fresh surface can be recommended. SHS products were composed of NiTi with the admixture of Ti2Ni phase. The formation of this phase cannot be fully avoided in SHS preparation route. [ABSTRACT FROM AUTHOR]

Abstract: The microstructure and crystallization behavior of a conventionally cast Fe-38 at.% Al-1 at.% C alloy and a set of crystals obtained from this alloy by the Bridgman and the floating-zone methods were investigated. A significant redistribution of elements during crystallization was observed. A two-phase microstructure of the κ-phase in the B2 matrix was found in regions with composition below 37 at.% Al and 0.5 at.% C. A microstructure consisting of the κ-phase and B2 matrix with a limited amount of graphite globules was obtained in the fast-solidified Bridgman sample. An enhanced growth of graphite lathes in the Bridgman crystal was observed at a growth rate of 28 mm h−1. These graphite lathes were oriented parallel to the {100} and {110} planes. The κ-phase precipitates have no orientation relationship with the matrix. [Copyright &y& Elsevier]