Thermal stability and oxidation behavior of nanostructured Ni-Al alloys with a high fraction of low angle grain boundaries

Conventional nanocrystalline dominated by high angle grain boundaries (HAGBs) possesses excellent oxidation resistance in air but poor thermal stability. Low angle grain boundaries (LAGBs) can improve its thermal stability, but effect on oxidation behavior is unclear. In this work, a nanolaminated Ni-7 wt% Al alloy with grain size of 56 nm and 85 % fraction of LAGBs was prepared, exhibiting higher thermal stability than conventional nanocrystalline at 800 ◦C. Its oxidation resistance is superior to coarse-grained alloy, but inferior to the HAGBsrich nanograins due to lower diffusion coefficient of LAGBs. This provides guidance for designing thermally stable and oxidation-resistant nanostructured alloys.