A Review of Expansion Measurements for Subsecond Ohmic Pulse-Heating Experiments

摘要

During fast pulse-heating experiments wire shaped specimens are rapidly ohmic heated by a short current 'pulse'. Within such a measurement various quantities can be recorded in a subsecond time regime. Amongst electrical current, voltage drop, and temperature the geometry of the sample (or its density) and its change during one experiment is an important parameter. The ultrashort experimental duration is a specific characteristic of pulse-heating and it is a major difficulty as well, because data recording has to be fast enough. Several laboratories around the globe have approached this requirement differently, and the developments of new electronic devices have risen new possibilities of measurements. Expansion measurements can be categorized into two groups: Interferometric techniques and optical imaging techniques. The workgroups considered in this review are for the millisecond time regime - NIST (former NBS) Gaithersburgh Maryland USA, INRIM (former IMGC) Turin Italy, and OGI Leoben Austria-as well as for the submicrosecond time regime-Christian Albrecht University Kiel Germany (several parts of their equipment moved later to TU Graz), Group M6 Los Alamos National Laboratory USA, CEA Valduc France, INP University of Greifswald Germany, and the Russian Academy of Sciences Moskow Russia. The development of expansion measurements during the last 25 years especially at the workgroup of subsecond thermophysics at TU Graz will be highlighted.