The effect of Fe, Cu, Zr, and Ti substitution on magnetic properties of SmCo 1 : 7 magnets at temperatures up to 500 degreesC were studied. As-milled amorphous Sm(Co,Fe,Cu,Ti-Zr)(7) magnets crystallized in the TbCu7-type structure after annealing at 750 degreesC for 2 h. A room-temperature intrinsic coercivity of around 2.5 T is obtained for compositions SmCo6.4 Zr-0.2 Ti-0.4 and SmCo6.4Fe0.1Zr0.1Ti0.4. The high coercivity of the ball-milled SmCo7-xTix magnets is attributed to the strong pinning of the walls of the ``interaction domains'' by the network of grain boundaries between the nanocrystalline grains. The virgin curve of the ball-milled samples is suggestive of strong domain wall pinning.