Each material class trades off stiffness, brittleness and thermal behavior differently. Heating raises atomic vibration amplitude; stretching strains inter-atomic bonds until some snap (fracture) past the material's failure strain.
σ = E · ε (Hooke's law, until failure)
vibration amplitude ∝ √T
- Temperature — drives atomic thermal vibration (jiggle) amplitude in the lattice.
- Applied strain — stretches the lattice along one axis; bonds beyond the material's failure strain break (turn red, then vanish).
- Material — metal (ductile, ~110 GPa), ceramic (very stiff but brittle, ~350 GPa), polymer (soft and flexible, ~3 GPa).
Real-world use: materials-discovery labs run exactly this kind of stress/temperature screening (physically or via molecular dynamics) to select alloys, coatings or polymers for a target application.