Manufacture and microstructure performance of H13-TiC gradient composite coating made by laser cladding

In order to solve the coating's general peeling and cracking problems caused by thermal stress at high temperature, H13-TiC gradient composite coatings were made by laser cladding on the surface of H13 hot-work die steel substrates. Using scanning electron microscope, X-ray diffraction and energy dispersive spectrometry, the microstrueture and morphology, distribution of constituents, hardness and thermal stability were checked. The results show that the coating mainly consists of Fe-Cr, TiC, TiO_2 and FeTC_3. Polyhedron and dendritic TiC particles were dispersed in the coating. With the rising of TiC, TiC particles become larger, the hardness of the gradient coating is gradually improved, the dendritic structure in the bonding zone become smaller, and their distribution is in gradient. After heating at high temperature of 600℃ and cooling in the air, the decrease of the hardness is the largest in remehing region among the layers, while the substrate H13 steel is in the second place. On the whole, the hardness distribution of the coating is still in gradient. H13-TiC gradient composite coatings made by laser cladding have a great potential for applications.