Influence of niobium addition on the high temperature mechanical properties of a centrifugally cast HP alloy

The influence of niobium addition on the mechanical properties at high temperature of HP alloy has been investigated. Two HP alloys were centrifugally cast with a similar chemical composition differing only in the niobium content. Low strain rate high temperature tensile tests and creep-rupture tests were performed in the range of 900-1100 °C, and the results compared between the alloys. According to the results, the high temperature mechanical behavior of both alloys is controlled by several factors like solid solution, network of eutectic carbides, intradendritic precipitation and dendrite spacing. A significant increase in the mechanical properties for the HP alloy with niobium addition was found within the temperature range of 900-1050 °C. Beyond this temperature the mechanical behavior of both alloys is basically the same.