Consolidation of MA amorphous NiTi powders by spark plasma sintering

Spark plasma sintering, as a recent innovation in rapid powder consolidation was used to sinter amorphous NiTi alloy obtained from mechanical alloying. Densified samples with Ni3Ti, NiTi and NiTi2 phases were produced. The grain sizes were retained to within 500 nm at the sintering temperature of 900°C and 1 μm for the sintering temperature of 1100°C. Based on the results of SEM and TEM, it is found that the formation of crystalline structure is controlled by solid state reaction when the sample was sintered at 900°C, but in the sample compacted at 1100°C, liquid was introduced for the low melting point phase NiTi2 melt. The products after sintering associated with the advantage of spark plasma sintering and the property of amorphous NiTi alloys after mechanical alloying is discussed.