- Impact Energy
- Imperfection (Crystal)
- Index of Refraction
- Inhibitor
- Insulator
- Integrated Circuit
- Intergranular Corrosion
- Intergranular Fracture
- Intermediate solid solution
- Intermetallic compound
- Interstitial Diffusion
- Intrinsic Semiconductor
- Ionic bond
- Isomerism
- Isomorphous
- Isotactic
- Isothermal
- Isothermal Transformation Diagrams
- Isotopes
- Izod Test