14. Creep Failure Flashcards
List the three regimes of creep
- Primary creep
- Secondary (steady-state) creep
- Tertiary creep (rupture)
Describe the effect of temperature and stress on creep
Increased stress = increased creep
increases temperature = increase creep
Describe material advancements that increase resistance to creep
- make a single crystal
- make channels for air cooling
- thermal coating which makes the material more heat resistant
Why does the creep rate continuously decrease during primary/instantaneous creep?
strain hardening
Why is the creep rate constant during secondary/steady-state creep?
due to balancing of strain hardening and recovery
Which creep regime is the longest?
secondary/steady-state creep
Which creep regime is the longest?
secondary/steady-state creep
As stress and/or temperature increase, the rupture time tr ______
decreases
As stress and/or temperature increase, the steady-state creep rate ______
increases
What is m in this equation?
𝑚 = 𝑇(𝐶 + log(𝑡𝑟))
the Larson-Miller parameter
Metals with a ____ melting temperature demonstrate greater resistance to creep
high
Metals with a ____ elastic modulus demonstrate greater resistance to creep
high
Metals with a ____ grain size demonstrate greater resistance to creep
large
Metals with a ____ grain size demonstrate greater resistance to creep
large
How does creep occur?
By the sliding of grain boundaries?
