work hardening

https://dx.doi.org/10.1351/goldbook.W06685
Opposite of work softening, in which shear results in a permanent increase of viscosity or consistency with time.
Source:
PAC, 1979, 51, 1213 (Manual of symbols and terminology for physicochemical quantities and units. Appendix II: Definitions, terminology and symbols in colloid and surface chemistry. Part 1.13. Selected definitions, terminology and symbols for rheological properties) on page 1217