Yttrium addition to heat-resistant cast stainless steel

Yttrium addition to HP-type (where H stands for heat-resistant and P is related to the Ni content) heat-resistant cast stainless steel resulted in increased fragmentation of the primary chromium carbide network and improved high temperature mechanical properties. The improvement was caused by yttrium carbide particles acting as nucleation sites for other carbides, as indicated by transmission electron microscopy and energy dispersive X-ray spectroscopy analysis. Thermodynamic considerations support these conclusions.