The structure and properties of pre-alloyed NiAl-Cr(Co,Hf) spherical powders produced by plasma rotating electrode processing for additive manufacturing

摘要

The structure and properties of pre-alloyed Ni41Al41Cr12Co6spherical powders (the 40–160μm fraction) produced using the plasma rotating electrode processing technology were studied. The evolution of the fine structure of pre-alloyed Ni41Al41Cr12Co6spherical powders under heating at 20, 350, …, 850°C was investigated. Disk-shaped chromium-rich pre-precipitation zones 5–30nm in size were detected in the temperature range of 450, …, 650°C; they precede the formation of the dispersed chromium precipitate. Prism-shaped chromium nanocrystals with the characteristic longitudinal dimension ranging from 15 to 100nm, whose nucleation process starts at prismatic dislocation loops, were found to be formed at 750, …, 850°C. The Young's modulus, hardness, and elastic recovery of powder material were determined by nanoindentation measurements. The resulting powders are characterized by bulk density of 3.8g/cm3, excellent flow rate (3.5s), and the angle of repose of 19.6°.