SUPERALLOYS - New Mexico Tech: New Mexico Techljacobso/Superalloy Slides.pdf · Please email me a...
Transcript of SUPERALLOYS - New Mexico Tech: New Mexico Techljacobso/Superalloy Slides.pdf · Please email me a...
METE 327 Physical Metallurgy Copyright 2008 Loren A. Jacobson 5/16/08
SUPERALLOYS
METE 327Fall, 2008
METE 327 Physical Metallurgy Copyright 2008 Loren A. Jacobson 5/16/08
OUTLINE Historical perspective Applications Compositions Processes Properties
− Creep
METE 327 Physical Metallurgy Copyright 2008 Loren A. Jacobson 5/16/08
Applications Gas Turbine Engines
− Blades, vanes, disks, combustors Space Vehicles
− Rocket motors Nuclear Reactors Submarines Petroleum Equipment
METE 327 Physical Metallurgy Copyright 2008 Loren A. Jacobson 5/16/08
Compositions Ni, Co and Fe Based Alloys Solid solution strengthening
− Cr, Mo, Al, Nb, Ti and others Precipitation strengthening
− Mostly due to Al and Ti− Ni3(Al,Ti), gamma prime− Lattice mismatch, amount, size and morphology
Carbide phases− M23C6, M6C or MC− M can be Cr, Ti, Mo or W
METE 327 Physical Metallurgy Copyright 2008 Loren A. Jacobson 5/16/08
Astroloy Microstructure (orig. 15 K X)
METE 327 Physical Metallurgy Copyright 2008 Loren A. Jacobson 5/16/08
CREEP Deformation at high temperature under
constant load Important property of Superalloys Brief discussion now, more next time
METE 327 Physical Metallurgy Copyright 2008 Loren A. Jacobson 5/16/08
Engineering Design Using Creep (and Stress-Rupture)
The Larson-Miller Parameter:
Stress Rupture Data Plottedaccording to the followingequation:
Where M = log e
and θ = t exp (-Q/RT)
assuming that Q and θ are functions of stress only. t can be atime to rupture or a time to a given creep strain.
Engineering Design Using Creep (and Stress-Rupture)
The Larson-Miller Parameter:
Stress Rupture Data Plottedaccording to the followingequation:
Where M = log e
and θ = t exp (-Q/RT)
assuming that Q and θ are functions of stress only. t can be atime to rupture or a time to a given creep strain.
METE 327 Physical Metallurgy Copyright 2008 Loren A. Jacobson 5/16/08
Assignment Please email me a question about superalloys
before Monday, 17 November [email protected] More about creep next time, and Materials
Selection for Design