Zr48Cu36Ag8Al8合金纳米材料的晶界扩散行为

Grain boundary diffusion behavior of Zr48Cu36Ag8Al8 alloy nanomaterial

通过对Zr（48）Cu（36）Ag8Al8非晶合金在过冷液相区等温热处理的方法制备了纳米材料,采用磁控溅射法获得了Ni/Zr（48）Cu（36）Ag8Al8纳米材料扩散偶,利用二次离子质谱法研究了Ni原子在纳米材料晶界原子扩散机制。结果表明：在703~723 K温度范围内,α与β参数均满足B类型区域扩散特点。根据Suzuoka方程解可以获得晶界扩散系数δD（gb）与温度之间的关系曲线,通过拟合发现：晶界扩散系数δD（gb）服从Arrhenius规则,同时Ni原子在两种纳米材料晶界处的扩散激活能均呈现出相同值,即Q（gb）≈1.433 e V。该结果说明不同状态纳米材料可能具有相似的微结构;此外,由于通过等温退火法获得的纳米材料中存在三叉晶界,内部可能存在一定数量的准空位,当外界提供能量时,外来原子可能通过原子跳跃以及多原子方式进行运动,从而降低整个体系的Gibbs自由能。同时与粗晶态合金相比,也进一步证实了晶态材料的原子扩散行为主要取决于晶界数量及拓扑结构。

Zr（48）Cu（36）Ag8Al8nanomaterial was prepared by isothermal annnealing of the Zr（48）Cu（36）Ag8Al8bulk metallic glass in the supercooled liquid region.Then,Ni/Zr（48）Cu（36）Ag8Al8nanomaterial diffusion couple was obtained by using magnetron sputtering.The mechanism of Ni atoms in grain boundary diffusion of Zr（48）Cu（36）Ag8Al8nanomaterials was analyzed by using secondary ion mass spectrum（SIMS）.The results show thatαandβboth meet diffusion feature of the B type area in the temperature range of 703-723 K.According to Suzuoka solution of equation,the relation curve between grain boundary diffusion coefficientδD（gb）and diffusion temperature is fitted calculation.Grain boundary diffusion coeffcientδD（gb）obeys the rules of the Arrhenius,and the activation energy of grain boundary diffusion in two kinds of nanomaterials is approximately equal（Q（gb）≈1.433 e V）.This phenomenon indicates that different state nanomaterials may have similar microstructure.In addition,a certain amount of space exists in the trigeminal grain boundary of nanomaterials obtained by the isothermal annealing method when there is an external energy function.So atoms will jump by single atom and more atoms cooperative movement,thereby reduce the Gibbs free energy of the whole system.It is also proved that the atomic diffusion behavior of the crystalline material is mainly dependent on the number of grain and the topological structure by compared with diffusion behaviors of the coarse grain.