Synthesis of nonequilibrium Ni-Hf binary alloys were carried out using laser cladding technique. In this process mixed powder in the ratio of Ni-26 wt% Hf was delivered using a screw feeder into a melt pool of the substrate, generated by a high power continuous wave CO2 laser beam. The microstructure of the claddings thus produced were investigated using optical, scanning and transmission electron microscopy and X-ray microanalysis techniques. Due to the inherent rapid cooling rate associated with the process of laser cladding process, some nonequilibrium hereto unreported phases formed in the claddings. There is also an extension in the solid solubility of Hf in the terminal α phase as compared to the equilibrium Ni-Hf binary phase diagram. This paper investigates this solid solubility extension, the evolution of the microstructure in the claddings in the system and also characterizes the metastable phases formed in terms of crystal structure and microchemistry. A nonequilibrium phase diagram for Ni-Hf binary alloy is recommended based on the micro-chemistry and differential thermal analysis data.
|Original language||English (US)|
|Number of pages||10|
|State||Published - Jan 1 1989|
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