creep strength

Interactions with the environment can significantly influence their high-temperature creep strength.

Long term creep strength is also higher.

The nickel-based superalloys have improved creep strength with the addition of rhenium.

This is reflected in softening of the materials together with reductions in their tensile and creep strengths.

Refractory elements such as rhenium and ruthenium can be added to the alloy to improve creep strength.

The creep strength was, however, reduced by tempering at 835°C due to rapid recovery of the martensitic structure with a sharp decrease in dislocation density.

This is not critical and variations in curing-time and/or temperature may be used to increase shear and creep strength at temperatures above 60 C (140 F).

In addition to other microstructural parameters, the state of the precipitates plays an important role for microstructural stability which is a prerequisite for long term creep strength.

In addition, it is often beneficial for grain boundaries that the nickel-base superalloy contains carbides (or boron or zirconium) for improvements in creep strength.

For most applications high conductivity copper is used but for heavy duty work it is usual to use a silver-bearing copper to obtain increased creep strength at operating temperature.

The development of de-alloyed zones during oxidation of martensitic and austenitic steels and Ni based superalloys has been reviewed and the influence of de-alloying on local creep strength has been assessed.

Titanium alloys are heat treated for a number of reasons, the main ones being to increase strength by solution treatment and aging as well as to optimize special properties, such as fracture toughness, fatigue strength and high temperature creep strength.

Hafnium can be alloyed with small amounts of other elements; e.g. tin and oxygen to increase tensile and creep strength, iron, chromium and niobium for corrosion resistance, and molybdenum for wear resistance, hardness, and machine ability.

The equation for power-law creep, where the strain rate is dependent upon the diffusion-controlled climb of edge dislocations, is found to yield realistic values of creep strength and viscosity, when the experimentally determined parameters for dry olivine are used.

The lowest creep strength was found for the P92 steel subjected to a heat treatment that produced a fully ferritic microstructure; the secondary creep rate was four orders of magnitude higher than that of the steel in the usual martensitic condition.

By this point several high-temperature alloys had become available with creep strength up to 700 C, and Constant demonstrated that using these materials in an engine would produce what would now be called a turboprop that would outperform existing piston engines except at very low altitudes.