Why test mechanical properties at temperature
Solders in electronics, polymer housings near engines, coatings on turbine and tool surfaces, and medical polymers sterilised by heat all work above room temperature. Hardness, stiffness and creep resistance can change dramatically as temperature rises, especially near a polymer’s glass transition or a solder’s homologous temperature. Room-temperature data alone can badly overestimate performance.
How the module works
The indenter tip and the sample are both placed inside an enclosed oven. Oven versions reach 275, 450 or 600 °C on the micro module and 275 or 450 °C on the nano module, whose piezoelectric actuator also runs nanoindentation DMA. Because they share the same environment, they reach the same temperature before contact. The hot zone uses MACOR components with a thermal expansion coefficient below 10⁻⁶ /°C, so the measuring geometry stays stable as temperature changes.
The thermal drift problem
At room temperature, the depth sensor measures only the indenter’s penetration. At high temperature, anything that expands or contracts during the test, such as the tip, the sample, the holder or the frame, also shows up as displacement. Drift is worst when a cold tip contacts a hot sample, because heat flows through the contact during measurement. Heating tip and sample together, letting the system equilibrate, and using low-expansion materials all reduce drift. That is essential for reliable modulus and, above all, for creep measurements, which are themselves slow changes in depth.
Polymers and the glass transition
Polymers change most around their glass transition. NANOVEA has published a method that locates the glass transition locally: periodic indentations at a fixed force while heating, with depth rising sharply as the material softens.
Solders and joints
Solder joints operate at a large fraction of their melting temperature, where creep and softening govern reliability. Nanoindentation at temperature measures these properties on the actual joint material. For the shape change itself, NANOVEA has published an in-situ 3D measurement of a solder as it melts and spreads between room temperature and 400 °C.
