ZrO2/Mg composites were prepared with friction-stir processing (FSP) using different ZrO2 amounts. The effects of FSP on the microstructure, mechanical properties and damping capacities of ZrO2/Mg composites are discussed in this paper. After friction-stir processing, the central region of the stir zone of a ZrO2/Mg composite obtained fine, uniform, equiaxed crystal grains. An addition of ZrO2 can obviously refine the grains and improve the microhardness and mechanical properties of ZrO2/Mg composites. The ZrO2/Mg composites prepared with friction-stir processing have better damping capacities. During a strain-damping test, the damping behavior of ZrO2/Mg composites follows the Granato-Lücke dislocation damping theory (G-L theory). The ZrO2/Mg composites with a groove width of 0.8 mm had the best damping capacities. Avtorji so pripravili ZrO2/Mg kompozite z vrtilno tornim postopkom (FSP, angl.: friction stir processing) z razli~no vsebnostjo ZrO2. V~lanku opisujejo vpliv FSP postopka na mikrostrukturo, mehanske lastnosti in sposobnost za du{enje izdelanih ZrO2/Mg kompozitov. Po izvedenem FSP postopku je v centralnem delu ZrO2/Mg kompozitov (v coni me{anja oz. vrtenja) nastalo homogeno podro~je drobnih enakoosnih kristalnih zrn. Dodatek ZrO2 je o~itno udrobnil mikrostrukturo kompozita, zvi{al mikrotrdoto in izbolj{al ostale mehanske lastnosti ZrO2/Mg kompozitov. Izdelani FSP ZrO2/Mg kompoziti imajo tudi bolj{e sposobnost du{enja. Deformacijsko-du{ilni preizkus je pokazal, da se karakteristika du{enja izdelanih ZrO2/Mg kompozitov dobro ujema z Granato-Lücke dislokacijsko teorijo du{enja (G-L teorija). Kompoziti ZrO2/Mg s {irino brazde 0,8 mm so imeli najbolj{o sposobnost du{enja. Klju~ne besede: ZrO2/Mg kompoziti, vrtilno-torni proces, sposobnost za mehansko du{enje, G-L teorija

Microstructure, texture and mechanical properties of a friction-stir-processed (FSPed) Mg-1Al-0.3Ca-0.3Mn-0.6Zn (w/%) alloy were investigated in the present work. During FSP, complete dynamic recrystallization (DRX) takes place in the coarse primary a-Mg matrix and a considerable grain refinement is achieved. Furthermore, DRXed grain sizes increase with an increase of the rotation speed from 1000 min-1 to 1600 min-1 , which is attributed to the integrated effect of the strain rate and thermal input. After FSP, a strong {0001} basal texture is formed, with the intensity ranging from 83.64 to 105.19. Compared to the base metal, the elongation is significantly enhanced, by »158 %, while the ultimate tensile strength and yield strength are reduced. The variation in the mechanical properties is mainly due to the grain refinement and strong {0001} basal texture obtained with FSP.