An Effect of Yttrium Micro-Additions on Properties of Heat-Resistant Ni-based Alloys
Yttrium is an effective micro-addition to the heat-resistant Ni-based alloys to improve their structure and properties. As a modifying element, yttrium contributes to the refinement of micrograins, a decrease in dendritic cell sizes and to the refinement and desired distribution of carbide phases in the structure of molten metal. Yttrium micro-additions increase heat resistance of alloys, neutralize the negative effect of sulfur and silicon, improve the thermal fatigue properties. Yttrium content as much as 0.01-0.05 % mass. is to be considered as the optimum.