Microscopic Mechanism of the Surface Interaction between Liquid and Solid Metals

用<87><10>声发射、电子显微镜、扫描隧道显微镜、X射线光电子能谱和电子探针等技术研究了Al、Al合金和Al_ Ni_ Ce_3非晶态合金的液态金属脆化（LME），发现Ga沉积在非晶态合金上使合金的断裂应力降低50%以上，并对合金的锯齿形应力-应变曲线起到一定的平滑作用。声发射观察到的无负载和定位样品的铝和铝合金在不同温度下退火。结果表明，即使在没有拉应力的情况下，Ga原子也可以通过晶界渗透到内部，并且施加应力加速了Ga原子的渗透。用扫描隧道显微镜观察了Ga沉积Al单晶的表面形貌，发现Ga沉积Al单晶的表面形貌与Ga沉积Al单晶的表面形貌相似，而Ga沉积Al单晶的表面形貌与Al单晶的表面形貌相似。我们观察到Ga在玻璃基片上蒸镀Al膜上的反常扩散。测量的扩散速度通常为几cm/h ;该值取决于膜厚度、衬底温度和退火温度。利用原子力显微镜、电子显微镜、XPS和EPMA等手段对这种反常扩散的机理进行了研究。

Liquid metal embrittlement (LME) of Al, Al alloys and amorphous alloy Al_<87>Ni_<10>Ce_3 was studied using various techniques such as acoustic emission, electron microscopy, scanning tunneling microscopy, x-ray photoelectron spectroscopy and electron probe micro analysis.Ga deposition on the amorphous alloy was found to cause an over 50% reduction in the fracture stress of the alloy, besides, to play a role somewhat in smoothing its serrated stress-strain curve. Acoustic emission was observed for both non-loaded and locaded samples of Al and Al alloys annealed at various temperatures. Results indicate that Ga atoms can penetrate the interior through grain boundaries even in the absence of tensile stress, and that the penetration of Ga atoms is accelerated by applied stress. This AE technique has proved to be very usefull for predicting the occurrence of LME in these materials.Scanning tunneling microscopy was employed to investigate the detailed surface appearance of Al single crystals deposited by Ga. The obtained images strongly suggested the formation of Al-Ga alloy.We noticed anomalous Ga diffusion over evaporated Al films on glass substrates. The diffusion velocity was measured to be typically a few cm/h ; the value depended on film thickness, substrate temperature and annealing temperature. The mechanism of this anomalous diffusion was investigated using atomic force microscopy, electron microscopy, XPS and EPMA.