What are the major considerations that have to be taken into account of suitable creep resistant alloys

High Temperature Strength: Alloys used in application requiring creep resistance must be able to retain their strength and retain their shape at high temperatures.

High Melting Point: Alloys used in high temperature application must have high melting points, as this increases their ability to resist creep.

Oxidation Resistance: Oxidation and corrosion can weaken alloys over time, which is why alloys used for application requiring creep resistance must have good oxidation and corrosion resistance.

Good Thermomechanical Properties: Creep resistance alloys must also have good thermomechanical properties, such as ductility and elasticity, so they can maintain their strength over a range of temperature conditions.

Cost: Alloys used in application requiring creep resistance may be more expensive than others, and cost should also be taken into consideration when selecting a suitable alloy.

Update (2023-11-21):
for various temperature conditions?

Alloy composition: The choice of suitable alloy composition is important for achieving the desired level of creep resistance. Alloying elements such as chromium, molybdenum, tungsten, vanadium and manganese can be added to improve the creep resistance of ferrous based alloys. However, these alloying elements often also increase the cost of the alloy and reduce its corrosion resistance. 

Work hardening: If a material is adequately work hardened it can often be made more resistant to creep. This is usually done by methods such as cold/hot working and shot peening.

Thermal stability: Alloys must be thermally stable at the range of temperatures that they will be exposed to, to minimise the risk of creep. The thermal expansion rate of the alloy must also be matched to the structure it is being used in.

Stress intensity: Stress intensity, usually expressed in terms of strain rate, is an important factor in determining creep resistance. Alloys with high strain rate resistance are generally better creep-resistant alloys.

Thermomechanical cycling: The number of thermomechanical cycles that the alloy can withstand is an important consideration for most creep resistant applications. High-temperature and long-time exposures can have a negative effect on creep resistance. 

Grain size: The grain size of the material is also an important factor in creep resistance. Smaller grains are known to increase creep resistance.