1 research outputs found
Origin of the Significant Impact of Ta on the Creep Resistance of FeCrNi Alloys
Heat resistant FeCrNi alloys are widely used in the petrochemical industry
because they exhibit a unique combination of creep and oxidation resistance at
temperatures exceeding 900C. Their creep properties are often optimized
by micro-additions of carbide forming elements. In the present work, the
influence of Ta micro-additions has been experimentally investigated both on
as-cast and aged microstructures to understand the origin of the significant
impact of this element on the creep resistance. Calculations with thermocal
software were also carried out to support experimental data. It is shown that a
small addition of Ta is beneficial as it increases the volume fraction of
stable MC carbides. We demonstrate also that additions of Ta may have a
dramatic effect on the thermal stability of microstructures. This is attributed
to a smaller equilibrium volume fraction of M23C6 and more pronounced
heterogeneous precipitation at MC/matrix interfaces. The influence on the creep
properties in then discussed