AbstractDeformation mechanisms during uniaxial compressive loading of two extruded binary Mg − 3Nd and Mg–3Y alloys (wt.%) were studied by advanced acoustic technique and electron microscopy. Particularly, a contribution of rare earth metals on the microstructure and resulting mechanical properties is addressed with respect to the extrusion direction. The extrusion of both investigated alloys was performed with the same processing parameters. Thus, the differences in initial microstructures and textures is caused by alloying elements. Consequently, deformation behavior of investigated alloys significantly depended on both the content of the alloy and mutual orientation of extrusion direction and deformation axis due to texture. The activity of individual deformation mechanisms during loading was elucidated using the acoustic emission (AE) technique including advanced adaptive sequential k-means (ASK) algorithm analysis. The results of the AE analysis were related to microstructure evolution provided by the electron backscatter diffraction (EBSD) technique, including Schmid factor analysis. The obtained results had shown that activity of the basal slip system was predominantly affected by the texture, whereas the activity of non-basal slip systems and twinning was dependent on both texture and type of rare earth metal in the alloy.