The aim of this diploma thesis was the visualisation of the local deformation behaviour of high-strength powder metallurgically (PM) produced tool steels to investigate the damage initiation of the different materials. The tool steels consist of a tempered martensite matrix and embedded hard phases (carbides). In order to observe the local deformation behaviour of the tool steels, pictures were taken in the scanning electron microscope at several load steps. Subsequently, the local strain and rotation fields were evaluated by means of a local deformation analysis. Up to now, this methodology was applied only for materials with low yield strengths. A question was whether this method can be applied for materials with very high yield strength and low elongation at fracture. Because of the low ductility of the materials, in-situ compression tests were chosen instead of in-situ tensile tests. To do this, the loading equipment was altered and cuboid-shaped compression specimens were machined. Different tool steels with different heat treatment conditions were tested, and the results were discussed.