EFFECT OF ALLOYING ELEMENTS ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF NiAl-Cr(Mo) EUTECTIC ALLOY
Microstructure and mechanical properties of NiAl-Cr(Mo) eutectic alloy and the effect of 0.1Fe,1Nb,4Ti additions are investigated at room temperature (RT) and high temperature (1000°C). The alloys are prepared by arc melting method and then homogenized at 1300°C in Ar atmosphere for 24 h. In addition to the room temperature and high temperature compression tests and X-ray diffraction measurements, hardness measurements and microscopic analyses at room temperature are performed. NiAl-Cr(Mo) alloy exhibit fine cellular eutectic structure with coarse eutectic at interdendiric regions. However, the Nb and Ti addition reduced the formation of eutectic structure. Cr2Nb-type Laves and Ni2AlTi-type Heusler phases are observed in the XRD patterns of the Nb and Ti containing alloys respectively. Addition of Fe does not have important effect on the room and high temperature yield strength of the alloy, while the Nb and Ti increase the yield strength of the alloys at both temperatures.