The modern equipment and procedures in the Fraunhofer IWM thermophysical and thermomechanical labs enable us to determine temperature dependent material properties. These properties provide the essential basis for evaluating the effects of thermal loads on components. This substantiated data is necessary for FE- simulation in order to optimize production processes, contour accuracy and energy usage. We determine the following parameters:
Our approach to material testing enables simulation and interpretation of production processes, more detailed damage analysis, the development and qualification of new alloys and the optimization of material combinations. Our clients often need us to answer the following questions:
The thermophysical and thermomechanical material characterization that we offer is of specific benefit to manufacturers who work with metals, ceramics, synthetic materials, polymers and glass, as well as for process steps which include shaping, heat treatments, welding, warm forming and cold forming.
Our measurement results provide the reliable data necessary for simulations and help clients to optimize their processes while minimizing energy requirements.
Specific heat capacity using Differential Scanning Calorimetry (DSC)
Differential Scanning Calorimeter (DSC)
DSC measuring principle
A sample pan and a reference pan are placed on a platinum disk. When the furnace is heated, both pans consume energy and heat up, but the heat flow from each pan into its platinum disk takes place at different rates. This heat flow difference is measured by thermocouples in a differential set-up. Changes in the DSC signal allow for the analysis of the heat capacity as well as melting, phase transformations, evaporation, and other reactions within the material.
Thermal expansion using thermomechanical analysis (TMA)
Thermomechanical Analyzer (TMA)
TMA measuring principles
When using a thermomechanical analyzer, a specimen is attached to a rod and clamped with one end in a conductive displacement transducer. With this set up, changes in length can be measured while the specimen is heated in the surrounding oven. From the temperature dependent change in length Δl(T), the technical coefficient of linear expansion α is calculated:
Additionally, volumetric phase transformation, shrinkage and sinter processes can all be measured in the TMA.
Thermal diffusivity and heat conductivity using Laser Flash Analysis (LFA)
Laser Flash Apparatus (LFA)
LFA measurement principles
This measuring technique uses a laser as a heat source. The front of the sample is heated by a short laser pulse, and the heat is conducted through the specimen. An infrared detector measures the temperature increase as a function of time on the specimen’s backside. From this temperature profile and the specimen’s size the thermal diffusivity a(T) is computed. The heat conductivity of the sample material can be determined by using temperature dependent density from DIL and thermal capacity from DSC:
Thermomechanical testing of metal materials using the "Gleeble 3150"