CONSOLIDATION OF MA AMORPHOUS NITI POWDERS BY SPARK PLASMA SINTERING

Spark plasma sintering, as a recent innovation in rapid powder consoli dation was used to sinter amorphous NiTi alloy obtained from mechanica l alloying. Densified samples with Ni3Ti, NiTi and NiTi, phases were p roduced. The grain sizes were retained to within 500 nm at the sinteri ng temperature of 900 degrees C and 1 mu m for the sintering temperatu re of 1100 degrees C. Based on the results of SEM and TEM, it is found that the formation of crystalline structure is controlled by solid st ate reaction when the sample was sintered at 900 degrees C, but in the sample compacted at 1100 degrees C, liquid was introduced for the low melting point phase NiTi2 melt. The products after sintering associat ed with the advantage of spark plasma sintering and the property of am orphous NiTi alloys after mechanical alloying is discussed. (C) 1998 E lsevier Science S.A.