CHE 333 - Materials Science Review Flashcards

Vocabulary flashcards covering material classifications, controlling factors, atomic mechanisms, and mechanical properties based on Class 01 and Class 02 lecture slides.

Polymers

A traditional material class made of long molecular chains or networks of repeating molecular units, most often based on carbon, featuring covalent bonding within chains and secondary bonding among chains.

Composite

A combination of two or more material types designed for targeted performance.

Glass Classification

Classified as a ceramic in A-1 despite containing silicon.

Factors Controlling Material Properties

Composition, structure, and processing.

Categories of Material Properties

Mechanical, thermal, electrical, optical, magnetic, aesthetics, cost, environmental/social, durability, and functional properties.

Structure (Material Factor)

Refers to the phases present in a material and their distribution.

Materials Engineering

Concerned with using materials for specific applications, developing new materials, understanding material performance, and improving the performance of new and existing materials.

Engineering Stress

The stress calculated using force and original cross-sectional area.

Engineering Strain

The change in length divided by the original length.

Elastic Deformation

Recoverable, non-permanent deformation where bonds stretch under load at the atomic level and return to their initial configuration after unloading.

Plastic Deformation

Permanent deformation where atoms are displaced under load and remain displaced after unloading.

Young's Modulus ($E$)

The slope of the elastic portion of the tensile stress-strain diagram, which directly describes material stiffness.

Yield Strength ($\sigma_y$)

The stress at which $0.2\%$ plastic deformation is produced.

Proportional Limit

The maximum stress in the elastic region of a stress-strain curve.

Tensile Strength (TS)

The maximum engineering stress a material can withstand before failure.

Fracture Strength

The engineering stress at which fracture occurs.

Ductility

The ability of a material to deform plastically. Materials with ductility below $5\%$ are typically considered brittle.

Alumina

A ceramic material listed in A-2 as having a Young's modulus of $393\,GPa$ and zero listed ductility.

True Stress and True Strain

Stress and strain measurements that account for the instantaneous change in cross-sectional area.

Compressive Stress-Strain Testing

Testing method useful for materials that are challenging to measure in tension, such as materials too brittle to grip or certain made parts.

Poisson's Ratio

The ratio of transverse contraction strain to longitudinal strain, considered only in the elastic region in A-2 and approximately $0.33$ for metals.

Hardness

A measure of resistance of a material to surface plastic deformation, where a smaller indentation indicates greater hardness.

Implications of Large Hardness

High resistance to deformation from compressive loads and better wear properties.

Ceramics

A traditional material class with strong covalent or ionic bonding, described as stiff and strong but brittle and prone to fracture.

Metals

A material class that includes elements such as Gold (Au) and Aluminum, generally characterized by electrical and thermal conductivity.