A study of the deformation and failure mechanisms of protective intermetallic coatings on AZ91 Mg alloys using microcantilever bending

Lu, Mingyuan; Mead, James L.; Wu, Yueqin; Russell, Hugh; Huang, Han

doi:10.1016/j.matchar.2016.09.020

Cited by 14 publications

(7 citation statements)

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“…Various micro-mechanical testing techniques have been developed to characterize interfacial adhesion. Nanoindentation [ 8 , 9 , 10 , 11 , 12 ], nanoscratch [ 13 , 14 ], and micro-cantilever (MC) and micro-bridge (MB) bending [ 7 , 15 , 16 , 17 , 18 ] are widely used. From these, nanoscratch is considered to be a semi-quantitative approach [ 19 ], whereas top-surface nanoindentation has been used to measure the interfacial strength and toughness of a stiff dielectric film attached onto a comparatively ductile semiconductor substrate [ 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

“…MC and MB bending tests have been used to evaluate interfacial toughness, both applicable to embedded interfaces [ 7 , 15 , 17 ]. However, the suitability of MC and MB bending is limited to the interface of a stiff film on an ideally stiff substrate [ 18 ], as bending induced plastic deformation in ductile layers could prevent interfacial delamination from occurring or introduce additional complexity and substantial error to the analysis [ 21 ]. Hence, an interfacial adhesion quantification technique that can cope with plasticity is badly needed.…”

Section: Introductionmentioning

confidence: 99%

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Adhesion Evaluation of an Embedded SiN/GaAs Interface Using a Novel “Push-Out” Technique

Dehkhoda

Huang

2022

Micromachines

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Adhesion assessments of an embedded interface in a multilayer system that contains a ductile layer are challenging. The occurrence of plastic deformation in the ductile layer often leads to additional complexity in analysis. In this study, an innovative “push-out” technique was devised to evaluate the interfacial toughness (Gin) of the embedded SiN/GaAs interface in a Au/SiN/GaAs multilayer system. Focus ion beam (FIB) milling was utilized to manufacture the miniaturized specimen and scratching with a conical indenter was used to apply load. This approach effectively minimized plastic deformation in the soft Au layer while inducing tensile stress to the embedded SiN/GaAs interface. As a result, the Au/SiN bilayer detached from the GaAs substrate with little plasticity. The energy associated with the interfacial delamination was derived from analyzing the load–displacement curves obtained from the scratching test. The Gin of the SiN/GaAs interface was calculated by means of energy analysis, and the average Gin was 4.86 ± 0.96 J m−2.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Adhesion Evaluation of an Embedded SiN/GaAs Interface Using a Novel “Push-Out” Technique

Dehkhoda

Huang

2022

Micromachines

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“…A limited number of studies have applied the indentation of fabricated microscale structures to investigate interfaces [17,28]. Matoy et al [29], Hirakata et al [30], and Chan et al [31], used notched MC configurations to initiate delamination of SiO/W and SiO/Cu, Sn/Si, and Zr/hydride interfaces, respectively.…”

Section: Introductionmentioning

confidence: 99%

Inducing stable interfacial delamination in a multilayer system by four-point bending of microbridges

Mead

Huang

2017

Surface and Coatings Technology

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The ability to produce stable delamination of thin film multilayer interfaces is a powerful tool for studying the interfacial adhesion within microsystems. In this study, a technique involving the four-point bending of microbridges was applied to initiate stable interfacial delamination within a multilayer system. Microscale pre-notched bridges with clamped-ends were machined into an Al/SiN/GaAs multilayer using focus ion beam milling. A square flat-end indenter was used to induce bending of the bridge by two contact locations. Bridge failure occurred via substrate fracture at the pre-notch, followed by crack deflection, and stable interfacial delamination of the SiN/GaAs interface. Substrate fracture and delamination were identified within the obtained load-displacement curves as a pop-in and region of linear load reduction respectively.

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“…Among all these processes, the most popular technique is micromechanical testing of focused ion beam (FIB) milled miniature structures [8,9]. Some examples of studies that this technique to identify the mechanical properties of coatings were performed by Lu et al [7,10] After that, the experimental methodology of the project will be discussed. Then, the experimental results of the project will be revealed and discussed in the next session.…”

Section: Motivation and Problem Definitionmentioning

confidence: 99%

“…Microcantilevers and microbridges are currently widely used to measure the mechanical properties of coating materials by performing bending tests [31]. Microcantilevers can be manufactured by cutting and removing the coating material with tools such as focused ion beams (FIB) [7,10] and electrified saws and wires [32]. Or by additive methods such as photolithography, electroplating, and anodizing followed by chemical etching to remove any unnecessary material [30].…”

Section: Bending Of Microcantilevers/microbridgesmentioning

confidence: 99%

UQ eSpace

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Fabián²

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Ti-6Al-4V is widely used in aerospace, aeronautical and military applications due to its excellent mechanical properties, especially its high strength to weight ratio and corrosion resistance. Nevertheless, poor wear and oxidation resistance has limited the utilization of this material in broader applications. This is why hard ceramic coatings are typically applied to the surface of Ti alloy with the purpose to improve its tribological properties. Characterizing the fracture strength of the coatings layers becomes critical as it determines the lifetime and structural integrity of the protective coating in service. In this project, fracture strength characterization of two typical TiO2 coatings on Ti-6Al-4V alloy produced by laser cladding process was carried out. This was achieved by using a combination of focused ion beam (FIB) milling, nanoindentation and finite element analysis (FEA) techniques. Firstly, the Ti-6Al-4V substrates were coated with a layer of titanium oxide, using laser scanning speed of 300mm/s, and laser power of 100W and 150W. The metallurgical cross-sections of the coatings were then examined using an optical microscope to characterize the microstructure of the solidified oxide coating. A FEI SCIOS FIB Dual Beam system was then used to manufacture the micro-scale cantilevers on the coatings and nanoindentation tests were performed to bend the microcantilever beams to failure. The critical load and deflection were recorded. At last, FEA models were created to simulate the bending behaviour of the microcantilevers during the bending test. And the maximum tensile stresses generated as the cantilevers failed were then used as the fracture strength. This methodology allowed us to conclude that all the cantilevers failed in a brittle fashion. Also, both SEM images and FEA simulations agree that fracture was initiated close to the base given that the highest stresses were identified in this area. The mean fracture strengths of the coating materials were 7.79 and 7.68 GPa, respectively. A through error analysis was conducted. It was concluded that the accuracy of this methodology was affected by the following factors: • Manufactured cantilevers had some curvature and the cross-sections were not completely symmetric. However, the microcantilevers were modelled flat and symmetric in order to simplify the model. • Measuring the actual dimensions of the cantilever beams was challenging due to its rounded edges. IV | P a g e Henry RAMIREZ MECH4501-Engineering Thesis ACKNOWLEDGEMENTS This thesis project would have been impossible without the aid and support of my supervisor, Dr. Mingyuan Lu. For always having willingness to help me during the execution of this project, for her patience, enthusiasm, motivation and vast knowledge. I cannot imagine having a better mentor and supervisor than her. Besides my advisor, I would like to express my sincere gratitude to the lecturers from all the subjects I took during my studies at UQ. In special to Prof. Hal Gurgenci, Prof. Ross McAree, Dr. Jeff Gates and Prof. Kaz...

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A study of the deformation and failure mechanisms of protective intermetallic coatings on AZ91 Mg alloys using microcantilever bending

Cited by 14 publications

References 35 publications

Adhesion Evaluation of an Embedded SiN/GaAs Interface Using a Novel “Push-Out” Technique

Adhesion Evaluation of an Embedded SiN/GaAs Interface Using a Novel “Push-Out” Technique

Inducing stable interfacial delamination in a multilayer system by four-point bending of microbridges

UQ eSpace

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