Ta－O固溶体中的Snoek－K■ster弛豫

试样表面镀一薄层Ｔｉ，消除内耗测最过程中氧吸附的影响．在镀Ｔｉ的Ｔａ—Ｏ试样中详细研究了Ｓｎｏｅｋ—Ｋｏｓｔｅｒ弛豫．观察到了两个内耗峰（较低温度的ＳＫ１峰和较高温度的ＳＫ２峰）．考查之退火温度和氧含量对内耗峰的形状和稳定性的影响．ＳＫ１峰和ＳＫ２峰的激活能分别为１．４和２．１ｅＶ．用Ｓｅｅｇｅｒ的螺位错上的双弯结成核和迁移以及几何弯结的迁移理论解释了实验结果．通过理论和实验比较，得到的螺位错上双弯结形成能约为０．９ｅＶ，螺位错与氧原子的结合能约为０．３ｅＶ实验还发现，进一步冷加工对Ｓｎｏｅｋ峰的影响在实验误差范围内，可以略去不计．

SNOEK-KOSTER RELAXATION IN Ta-O SOLID SOLUTIONS

After coating the specimen with a thin Ti layer, the Snoek-Koster relaxation is systematically investigated without the effect of oxygen pick up. Two relatively stable internal friction peaks, SK1 at lower temperature and SK2 at higher temperature, are observed in deformed Ta-O samples. The changes of their peak shape and stability with annealing at different oxygen content are experimentally studied. The activation energies of SK1 and SK2 are measured to be 1 .4 and 2.1 eV respectively. It is suggested that the SK1 corresponds to the geometrical kink migration on screw dislocations and the SK2 corresponds to the formation and migration of kink-pairs on screw dislocations. From experimental results it is estimated that the energy of kink pair formation is about 0.9 eV and the binding energy of screw dislocation with oxygen atom is about 0.3 eV. It is additionally found that the height of the Snoek peak does not change after further deformation.