Transformation of Nanostructured Ni-Al Alloys Produced by Mechanical Alloying Methods

摘要

NiAl alloy powders were prepared by mechanical alloying method and bulk specimens were produced using vacuum hot pressing techniques. This study focused on the transformation behavior of Ni-Al mechanically alloyed powders and bulk alloys. Transformation behavior was investigated by differential scanning calorimeter(DSC), XRD and TEM. Particle size distribution and microstructures of mechanically alloyed powders were studied by particle size analyzer and scanning electron microscope (SEM). After 10 hours milling, XRD peak broadening appeared at the alloyed powders with composition of Ni-36at%Al to 40at%Al. The NiAl and Ni{sub}3Al intermetallic compounds were formed after water quenching of solution treated powders and bulk samples at solution treated powders. 1200°C, but the martensite phase was observed after liquid nitrogen quenching of solution treated powders. It is considered to be caused by fast diffusion of atoms for the formation of stable β(NiAl) phase and Ni{sub}3Al due to nano sized grains during quenching.