Ceramic-metal composite surface layers by laser processing

Ceramic–metal composite surfaces were formed by melting Tic– and TiN–particles into a die steel 90MnCrV8 (containing 0.9 %C) using a 3.5 KW CO2–laser. The particles (median size: 3 pm and 31 pm) had been preplaced on the substrate prior to laser treatment. Resulting microstructures consisted of about 40–60 vol.% hard phases homogeneously embedded in a martensitic matrix. Due to reduced melt pool convection by the processing method composite layers of uniform thickness and reduced particle dissolution had been obtained. Resistance to oscillatin sliding wear was measured using a laboratory tribometer with counterbodies of bearing steel and alumina, respectively. Both friction and wear of composites were decreased in comparison with the hardened untreated steel. Wear intensity depended on type and size of incorporated particles.