材料期刊网

应用金相及X射线衍射方法,并辅之以硬度测量研究了Mo-Ti-Zr,Mo-Nb-Zr两三元系的1200℃恒温截面。两合金系统的1200℃恒温截面很相似,包括一个单相区α及一个两相区(α+ε)。在Mo-Ti-Zr系中α为体心立方Mo-Ti-Zr三元固溶体,其点阵常数随固溶体中钛、铅含量的增加而增大,ε为三元Laves相(Ti,Zr)Mo_2,其结构与ZrMo_2相同。在Mo-Nb-Zr系中α为体心立方Mo-Nb-Zr三元固溶体,其点阵常数也随固溶体中铌、锆含量增加而增加,ε为具有MgCu_2型结构的三元Laves相Zr(Mo,Nb)_2。在Mo-Ti-Zr三元系中,随着钛含量的增加,合金的等硬度曲线呈半环状向钛角扩展,在Mo-Nb-Zr三元系中,随着铌含量的增加,合金的等硬度曲线也呈半环状向铌角扩展。

The isothermal sections at 1200℃ of the systems Mo-Ti-Zr and Mo-Nb-Zr have been determined by metallographic and X-ray diffraction methods supplemented by hardness measurements. The constitutions of these two systems are strikingly similar; besides a b.c.c, ternary terminal solid solution and a ternary Laves phase isomorphous with MgCu_2 structure, no new intermediate phase has been found.In the Mo-Ti-Zr system the lattice parameter of the ternary solid solution increases with the increase of Ti or Zr in solid solution, and the ternary Laves phase is (Ti, Zr) Mo_2. In the Mo-Nb-Zr system, the lattice parameter of the ternary solid solution also increases with the increase in the Nb- or Zr-content, and the ternary phase in this case is Zr(Mo, Nb)_2.The iso-hardness contours of the Mo-Ti-Zr system tend to expand towards the titanium corner as the Ti-content is increased, whereas those of the Mo-Nb-Zr system expand towards the niobium corner with the increase in Nb-content in a like manner.