Isotropic Thermal Expansion Properties of Cast Aluminum Plate
Cast aluminum plate delivers isotropic thermal expansion across all orthogonal axes due to its stress-relieved equiaxed grain structure.
Dilatometry
Meaning
Thermal analytical testing routines quantify dimensional variations in solid materials as a function of controlled temperature changes. In hardware integration, dilatometry measures coefficient of thermal expansion curves for printed circuit board substrates and potted encapsulants. The technique governs component strain matching across thermal cycling profiles from minus forty degrees Celsius to elevated soldering or operating temperatures.
Expansion Measurement
Push-rod instruments track micro-meter dimensional shifts while heating or cooling test samples under precise thermal ramps. Applying dilatometry yields differential thermal expansion curves that identify glass transition temperatures in resin substrates and printed circuit board laminates. Softening points and phase transformations appear as sharp slope shifts on dimensional change charts.
Engineers use these measured thermal expansion values to predict mechanical displacement in multi-layer board stacks during solder reflow processes.
Interface Stress
Mismatch in expansion rates between rigid components and underlying circuit boards generates shear stresses at solder joints and ball grid arrays. Executing dilatometry across composite material samples reveals critical dimensional mismatches prior to structural adhesive curing. Differential expansion between an aluminum chassis and an epoxy-encapsulated module creates micro-cracks under repeated temperature cycles.
Accurate material thermal expansion profiles guide structural adhesive selection to absorb interface strain and maintain thermal interface contact.
Operational Boundary
Measurement validity depends on uniform temperature distribution throughout the sample volume during thermal ramping. High-precision dilatometry requires solid test samples with flat parallel end faces to prevent mechanical alignment errors in the measurement push-rod assembly. The test procedure does not simulate localized dynamic thermal gradients caused by high-power operational components under localized electrical load.