190 likes | 682 Views
Plastic deformation of materials. deformation parameters. microstructural parameters. material parameters:. Constitutive laws of plastic deformation. kinetic. microstructural evolution. Mecking and Kocks (1981); Frost and Ashby (1982). Deformation tests (constant T ). constant strain rate.
E N D
Plastic deformation of materials deformation parameters microstructural parameters material parameters:
Constitutive laws of plastic deformation kinetic microstructural evolution Mecking and Kocks (1981); Frost and Ashby (1982)
Deformation tests (constant T ) constant strain rate constant stress (creep)
One parameter model of plastic deformation (r - model) creep *Kinetic Law const. strain rate * Structural evolution: (dr / de)
Compression Test Compression Cage P P initial state after creep P 10 mm
Creep rate for Stage II high T: Q = QL * Mukherjee-Bird-Dorn Equation * Norton Equation Sherby and Miller (1979) low T: Q = Qgb, Qp high s: n = 3-5 (power law creep: dislocations) low s: n = 1 (viscous creep: diffusion)
: time to fracture : minimum creep rate or, more general: Test of Monkman-Grant for Cu The Monkman-Grant Relationship for time to fracture where: 0.77<m<0.93; 0.48<BMG<1.3 for Al, Cu, Ti, Fe and Ni base alloys (from Monkman-Grant research)
ksi Fig a Engineering Estimates of Creep Behaviour Larson-Miller parameter (LM) ksi