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Investigation on the structural evolution of the mixture of Zr and hexagonal BN (h-BN) powders during mechanical alloying (MA) was performed by means of X-ray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy. The grain size of h-BN decreases rapidly with increasing milling time, which makes the diffraction peaks disappear at the initial stage of MA. And then most of the N and B atoms diffuse into Zr grains to form a (Zr, B, N) solid solution. An fcc phase Zr(B1−xNx) was found in the sample milled for about 40 h, and all the sample transformed into nanocrystalline Zr(B1−xNx) when the mixture was ball milled for longer than 48 h. The (Zr, B, N) solid solution may transform into Zr(B1−xNx) during annealing at about 900 °C, which confirmed that the formation of Zr(B1−xNx) is a diffusion process. |
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