Recently a number of in situ straining experiments have been carried out at temperatures between about 80 K and 1200 K. A new HVEM straining stage was constructed for temperatures above 1300 K. Its design features are: top entry double tilting stage, thermal expansion drive of high stiffness, heating by electron bombardment, and water cooling to quickly reach a steady state.The following deformation phenomena have successfully been treated by in situ experiments:Determination of the effective stress from the curvature of bowed-out dislocation segments: As shown by in situ experiments on MgO crystals, the line tension of dislocations may differ from its theoretical value. Nevertheless, the anomalous temperature dependence of the effective stress in ordered alloys as well as for prismatic slip in Be has been determined in accordance with macroscopic experiments. Measurement of velocities and kinematic behaviour of dislocations: In situ experiments allow the coordination of the motion of individual dislocation segments with their geometrical configuration.
Graphical Determination of Path Curves on Psychrometric Chart in Dehumidification and Water Cooling.
