An Introduction to Neutron Scattering - Spallation Neutron Source

Definitions of Stress and Strain
• Macroscopic strain – total strain measured by an extensometer
• Elastic lattice strain – response of lattice planes to applied
stress, measured by diffraction
d - d
e hkl =
d
hkl 0
• Intergranular strain – deviation of elastic lattice strain from
linear behavior
• Residual strains – internal strains present with no applied force
• Thermal residual strains – strains that develop on cooling from
processing temperature due to anisotropic coefficients of
thermal expansion
0
s
e I =ehkl -
E
applied
hkl