EFFECT OF RARE-EARTH METALS (Dy, Tb, Sm, Nd) ON STRUCTURE AND MECHANICAL PROPERTIES OF THE Mg-Y-Gd-Zr SYSTEM ALLOYS
Kinetics of ageing, structure and the strength characteristics of the Mg-Y-Gd-Zr system alloys of compositions near to that of the IMV7-1(~5%Y, ~5%Gd, ~0.5%Zr, remainder Mg) alloy were studied. It was established, that alloying of the Mg-Y-Gd-Zr alloys with Dy, Tb, Sm, Nd results in strengthening of them at room and elevated temperatures both in homogenized and in aged states. Meanwhile, after addition of samarium or neodymium the ageing time needed for substantial strengthening becomes shorter, after addition of terbium it did not change actually and after addition of dysprosium it became longer. Therefore, the strengthening ageing for the Mg-Y-Gd-Zr alloys after addition of Nd, Sm or Dy requires certain corrections.