Titanium micro addition in a centrifugally cast HPNb alloy: High temperature mechanical properties

The influence of titanium micro addition on the mechanical properties at high temperature of HPNb alloy has been investigated. Two seamless tubes were centrifugally cast with a Ti micro addition being the major difference between them. Hot tensile and creep rupture tests were performed in the range of 900–1100 °C combining different strain rates and stresses, respectively. The Ti micro addition in the HPNb alloy decreases the mechanical resistance in the hot tensile tests, but increases considerably the time to rupture and ductility in creep properties. Solid solution, carbide formation and precipitation play important roles controlling these properties. A change in the fracture mode associated with a change in the creep mechanism was reported for both alloys.