Year of Publication

2016

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Engineering

Department

Mechanical Engineering

First Advisor

Dr. Dusan P. Sekulic

Second Advisor

Dr. Kozo Saito

Abstract

Wetting and spreading of liquid systems on solid substrates under transient conditions, driven by surface tension and viscous forces along with the interface interactions (e.g., a substrate dissolution or diffusion and/or chemical reaction) is a complex problem, still waiting to be fully understood. In this study we have performed an extensive experimental investigation of liquid aluminum alloy spreading over aluminum substrate along with corroboration with theoretical modeling, performed in separate but coordinate study. Wetting and spreading to be considered take place during a transient formation of the free liquid surface in both sessile drop and wedge-tee mating surfaces’ configurations. The AA3003 is used as a substrate and a novel self-fluxing material called TrilliumTM is considered as the filler metal. In addition, benchmark, non-reactive cases of spreading of water and silicon oil over quartz glass are considered. The study is performed experimentally by a high temperature optical dynamic contact angle measuring system and a standard and high speed visible light camera, as well as with infra read imaging. Benchmark tests of non-reactive systems are conducted under ambient environment’s conditions. Molten metal experiment series featured aluminum and silicone alloys under controlled atmosphere at elevated temperatures. The chamber atmosphere is maintained by the ultra-high purity nitrogen gas purge process with the temperature monitored in real time in situ. Different configurations of the wedge-tee joints are designed to explore different parameters impacting the kinetics of the triple line movement process. Different power law relationships are identified, supporting subsequent theoretical analysis and simulation. Under ambient temperature conditions, the non-reactive liquid wetting and spreading experiments (water and oil systems) were studied to verify the equilibrium triple line location relationships. The kinetics relationship between the dynamic contact angle and the triple line location is identified. Additional simulation and theoretical analysis of the triple line movement is conducted using the commercial computer software platform Comsol in a collaboration with a team from Washington State University within the NSF sponsored Grant #1235759 and # 1234581. The experimental work conducted here has been complemented by a verification of the Comsol phase-field modeling. Both segments of work (experimental and numerical) are parts of the collaborative NSF sponsored project involving the University of Kentucky and Washington State University. The phase field modeling used in this work was developed at the Washington State University and data are corroborated with experimental results obtained within the scope of this Thesis.

Digital Object Identifier (DOI)

http://dx.doi.org/10.13023/ETD.2016.163

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