PHASE FORMATION IN NiTiAl10 POWDER MIXTURE DURING HEATING TO 1100 °C

Abstract

In this paper the comparison of NiTiAl10 wt. % with the binary NiTi46 wt. % prepared by powder metallurgy was researched. The method of combustion synthesis was carried out under following conditions: sintering temperature of 800 °C and 1100 °C and heating rate approx. 300 °C.min-1. The addition of aluminium to NiTi46 wt. % powder mixture completely changed the temperature of combustion synthesis and phase evolution during sintering. The reactions into Ni-Ti-Al powder mixture started below the melting temperature of aluminium and the new phases were formed in the material. The process of reactive sintering was studied by differential thermal analysis using the heating rate of 30 °C.min-1 and 100 °C.min-1. A combination of induction furnace and optical pyrometer. The addition of aluminium influenced microstructure significantly and increased the hardness of samples.