The thermal property triangle

Any two of these three quantities determine the third. Choose which one to solve for, then type the other two — or load a material to see typical values.

α = k / ρcp

Solve for:

Thermal conductivity k

W·m−1·K−1

input

Thermal diffusivity α

m2·s−1

solved

Volumetric heat capacity ρcp

J·m−3·K−1

input

Relative uncertainty (optional): u(k)/k u(α)/α u(ρcp)/ρcp

Values shown for presets are representative room-temperature figures for illustration, not certified reference data — real specimens vary with purity, density, orientation and processing history. Note that this simplified model assumes an isotropic material; for layered or fiber-aligned materials, k and α are direction-dependent and the triangle must be applied separately along each axis.