材料期刊网

用测量等温退火过程中试样的电阻变化对Pd(Fe,Co,Ni)_(0.05-0.15)Si_(0.17)金属玻璃的结晶动力学进行了研究。在等温退火过程中,试样的电阻下降一般为10—20％,Pd-Fe-Si系试样的电阻变化直接与含Fe量有关,Pd_(0.78)Fe_(0.05)Si_(0.17)在等温结晶中电阻反而升高。从动力学观点看,在Pd-Si系中添加Fe,Co和Ni使结晶活化能增加,结晶模式指数减小,从而使金属玻璃变得稳定。衡量金属玻璃的稳定性要同时考虑其热力学稳定性和动力学稳定性。

The crystallization kinetics of Pd(Fe,Co,Ni)_(0.05-0.15)Si_(0.17) and Pd_(0.84) Si_(0.16) metallic glasses has been monitored by determining the time dependence of electrical resistance during isothermal annealing below their own crystallization temperatures. It is found that the total drop of electrical resistance in the crystallization process is 10—20% generally, but the metallic glasses Pd-Fe-Si seemed to be something special and their electrical resistance was measured to be directly related to their Fe content. The electrical resistance of the metallic glasses Pd_(0.78)Fe_(0.05)Si_(0.17) increases during isothermal crystallization, yet the reason is not clear. From the viewpoint of kinetics, an addition of Fe, Co or Ni into Pd-Si system may increase their crystallization activation energy and decrease their crystallization mode coefficient, thus, makes them more stable owing to retarding the nucleation. It is believed that the stability of metallic glasses would be considered by both thermodynamic and kinetic basises other than the crystallization temperature.