Thermal stability up to 800 °c of a Ni-4 wt% Al nanocomposite

摘要

The thermal stability up to 800 °C of a nanocrystalline (NC) Ni (mean grain size ～25 nm) with ～4 wt% Al dispersed in the form of ～160-nm-sized particles, which was fabricated by co-electrodeposition from a nickel sulfate bath, has been investigated using differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results showed that microstructural evolution of the composite is temperature dependent, i.e., normal grain growth of the NC Ni, ～0.6 wt% Al solution into the Ni matrix and direct reaction between Al and Ni to form Ni3Al precipitates occurred at ～290, ～325 and ～575 °C, respectively. The distribution of Al in Ni matrix with temperature is fully discussed.