Detection of the fracture path under tensile loads through in situ tests in an ESEM chamber

In situ tensile tests parallel to the grain were carried out in an Environmental Scanning Electron Microscope (ESEM) chamber on Norway spruce ( Picea abies [L.] Karst.) samples. The ESEM-mode combined with a cooling device allowed examination of the specimens at a moisture content of 12% with unsputtered surfaces. By recording load-displacement curves and observing crack propagation simultaneously, a detailed image of fracture progress and tissue interaction could be described. Since these experiments required a sufficient specimen size and geometry, focus was concentrated on the methodology.