The intermetallic compounds formation and mechanical properties of composites in the Ni-Al system


Aluminum-nickel (Al-Ni) based intermetallic compounds are regarded as the promising materials for the high-temperature engineering applications, including harsh environments. So far, a satisfactory modeling has been done to analyze the structural properties, heats of formation, elastic properties and electronic energy band structures of Al-Ni intermetallic compounds. However, the experimental studies on Al-Ni intermetallic compounds formation and the data on the structure and mechanical properties are fragmentary in the literature. In the present work, the intermetallic compounds in Al-Ni system were obtained from nanonickel powder and micron-sized aluminum powders for the first time using modified powder metallurgy technique. Phase formation and structures of powders and consolidated materials were investigated via XRD, SEM, EDX and hydrostatic weighting. Via XRD it was shown, that despite the strong interactions between Ni and Al the formation of intermetallic compounds in the system is hindered. The density of consolidated specimens increases with nickel content increase. The sample 10nNi with the highest content of Al3Ni showed the best mechanical properties among the other specimens: Due to the reinforcement effect of the intermetallic compound, the sample with the highest content of Al3Ni showed the microhardness of 161±39 HV.