| Studying the wetting behavior and interfacial interaction between liquid and solid phase has increasingly becoming an interesting topic scientifically and an important subject technologically during the recent years especially with the ongoing development of high performance brazing, composites fabrication and electronic packaging industry. Connection (brazing, fusion wedding and Transient Liquid Phase Bonding (TLP)) is an indispensable processing method for materials fabricating to parts and structures. In these connection process involved with liquid phase, the wetting of liquid on solid and interface reaction determines the compatibility of the material junction, which to a large extent determines the possibility of connection and materials performance. Therefore, the wetting behavior of liquid on solid has important theoretical significance and practical application guide value for selecting the appropriate intermediate combination material and reasonable welding procedure. This work select Ti-based amorphous alloy melt and the Ti55 alloy as the research object. The following conclusions could be obtained:Firstly, optimizing the composition and characterizing the property of the experimental materials. Ti50.8Zr26.7Be22.5 was selected as the 1# original composition alloy and then three novel Ti-based amorphous alloy 2#,3#,4# were designed with 2% atomic ratio of Si substitution of Zr and Sn substitution of Ti and Zr. Alloy ribbons and rods of 2mm in diameter were fabricated and characterized. The results show that the original 1# amorphous alloy has a very limited glass forming ability (GFA) that is the ribbon sample has a lot of crystal phase in it. The modified 2# alloy has a better glass forming ability than the unmodified 1# alloy, which can form a nearly amorphous alloy ribbon with very little crystal phases.The 3# and 4# alloy has a much larger GFA, even the alloy rods of 2mm in diameter can form partical amorphous structure. The evolution of microstructure of Ti55 alloy with heat treatment were characterized. With the extension of holding time and increasing of heating temperature, five types of microstructure with distinctive characteristics were observed:the slender grains below 1173K and the mixture of slender grains and the isometric crystal region from 1173K to below 1223K. The isometric crystal region of the temperature range from 1223K to 1273K. Widmanstatten structure near the phase transformation point of Ti55 alloy and the coarsening of the microstructure above the phase transformation point of Ti55 alloy.Secondly, wetting dynamics between Ti-based amorphous alloy melt and Ti55 alloy.4 types of wetting system under different experimental conditions were conducted. Wetting dynamics of four types of amorphous alloy and Ti55 alloy system were characterized especially the evolution of contact angle and contact radius with time and temperature were plotted. The result shows that the contact angle decrease with the increase of heating temperature and holding time. Under the experimental conditions, nearly all the contact angle were ranged from 35° to 18°, which means that these alloy systems have a good wettability with the Ti55 alloy.Thirdly, liquid/solid interface interactions. Interfacial reactions and elemental diffusions under different experimental conditions were investigated. The interfacial reaction layer growth kinetics were characterized. The interfacial reaction layer thickness increase with the heating temperature and holding time, and the stronger the glass forming abilities of the alloy is, the smaller the interfacial reaction layer thickness is in the temperature range studied for the for alloy system. The apparent activation energy for the growth of the interfacial layer of four different wetting system were characterized. For 1#,2M,3# and 4# wetting system the apparent activation energy were 113.28kJ/mol,122.8kJ/mol,67.429kJ/mol and 78.406kJ/mol respectively. The interfacial layer growth is controlled by the element diffusion induced phase transformation mechanism when the temperature is below the phase transformation point of Ti55 alloy. |
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