Investigation of chromium effect on synthesis behavior of nickel aluminide during mechanical alloying process

The mechanical alloying process was used to synthesize the Ni50Al50−xCrx nanocrystalline intermetallic compound using the pure Ni and Al elemental powder. The mechanical alloying was carried out in the presence of various Cr contents as a micro-alloying element for various milling times. The synthesis behavior of final product was investigated by using XRD, SEM and EDS. Results confirmed that synthesis behavior of nickel aluminide intermetallic depends on the Cr content and milling time. The results revealed that for an inadequate milling time, the intermetallic phase is generated after opening the vial lid. The EDS results depict that the samples synthesized in the air atmosphere, i.e. after opening the vial lid, include a considerable value of oxygen. The X-ray map results reveal that, after opening the vial lid, the oxidation of milled aluminum particles will result in the generation of final product in the air atmosphere. According to XRD results, when the milling time is constant, increasing the Cr content leads to acceleration in the nickel aluminide formation in the air atmosphere.