Thermal fatigue properties of differently constructed functionally graded materials aimed for refurbishing of pressure-die-casting dies

Different surface layers, constructed on the basis of functionally graded materials using a laser cladding technique, were designed to study the possibility of using them in applications subjected to thermal fatigue. Three different filler materials, varying in terms of the concentrations of alloying elements were used. A graded chemical composition was achieved, varying the concentration of silicon from 0.1 wt.% at surface layer to 1 wt.% in the base material. A specially designed thermal fatigue test was utilized for the assessment of the thermal fatigue resistance of designed surface layers and compared with base tool steel AISI H13. The results of thermal fatigue testing showed that the different concentrations of alloying elements in the surface layers resulted in different thermal fatigue resistances. The thermal fatigue resistance was observed to be approximately 27 times higher in specimens with lower silicon content compared to base material. This was found to be closely correlated with the microhardness and the resistance to softening during annealing.