A functionally gradient TiC/Ni alloy composite coating was produced by one step laser cladding with pre-placed mixture powder on 045 steel substrate. The clad layer consists of TiC particles, gamma-Ni primary dendrites and interdendritic eutectics. From the bottom to the top of the clad layer, TiC particles exhibit a continuous increase both in size (from 0.8 µm to 4.5 µm) and in volume fraction (from 4% to 33%), and their morphology change correspondingly from small globe to coarse flower like cluster. The rapid coarsening of TiC particles during the solidification of laser pool results from the collision and sintering of particles. The preferential engulfing to a small cluster moving at slower speed by liquid/solid front leads to in-situ formation of the gradient structure of the coating.
|Translated title of the contribution||Laser clad TiCp/Ni alloy functionally gradient coating and its in-situ formation mechanism|
|Number of pages||5|
|Journal||Acta Metallurgica Sinica|
|Publication status||Published - Sep-1998|