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The mechanical properties and the deformation mechanism of Cu single crystal metal and bi-crystal Cu metals are explored by the molecular statics simulations for the nanoindentation and nanoscratching process. In the simulation of nanoindentation, the relationship of load, influenced depth and displacement are obtained to investigate the deformation mechanism of Cu metals. The variations of averaged bond length are used to understand condition of atoms deformation. For the nanoindentation on two single crystal surfaces, our results indicate that the influenced depths can be affected by the tip indentation and the motion of dislocations. In the case of the bi-crystal system, because the interfaces between two crystal orientations can provide the resistance to the motions of dislocation, the influenced depths can be affected by the existence of the interface. Eventually, the variations of averaged bond length are also used to explore the structural deformation under the different nanoindentation depths and nanoscratching distances during the nanoscratching process. Moreover, the deformation mechanism during nanoindentation and nanoscratching process are also discussed in this article.

The main goal of this study consists of the development of new asphalt mixes, based on industrial waste materials as replacement of natural aggregates. To achieve this purpose, a new characterisation of these pavements was proposed so to verify that the new mix has good mechanical performance without any detrimental impact to the environment. This characterisation was divided in three distinct steps: • a physical and chemical characterisation of the different constituents of asphalt concrete, as well the natural materials as the industrial waste considered as potentially secondary aggregates, • a study of the bitumen-aggregate interface by means of two techniques: a qualitative method (scanning electron microscope) and a quantitative one (nanoindentation) • an evaluation of the mechanical performance of mixes containing industrial waste, before and after recycling, by means of four standard road-engineering tests. The numerous results allowed to put in evidence the possibility to reuse some industrial waste materials in asphalt concrete. In addition, this characterisation containing both chemical and mechanical aspects, at the microscopic and macroscopic scales, would permit the transposition of this study to the whole of asphalt concrete./ Le principal objectif de ce travail consiste en le développement de nouveaux mélanges bitumineux utilisant des déchets industriels en tant que remplacement des matériaux naturels. Pour ce faire, une nouvelle caractérisation de ces revêtements a été proposée afin de vérifier que le nouveau revêtement obtenu présente de bonnes performances mécaniques tout en évitant un impact environnemental néfaste. Cette caractérisation a été scindée en trois étapes distinctes : • une caractérisation physique et chimique des différents constituants de l’enrobé bitumineux, à savoir les granulats naturels mais également les déchets industriels, candidats en tant que matériaux secondaires, • une étude de l’interface bitume-granulat et ce, au moyen de deux techniques : une méthode qualitative (microscope électronique à balayage)et une méthode quantitative (nanoindentation), • une évaluation des performances mécaniques des mélanges comportant des déchets industriels avant et après recyclage et ce, au moyen de quatre tests usuels de l’ingénierie routière. Les nombreux résultats obtenus ont permis de mettre en évidence la possibilité de valoriser certains déchets industriels dans les enrobés bitumineux. De plus, la mise en place d’une caractérisation comportant des aspects chimiques et mécaniques, à la fois à l’échelle microscopique et macroscopique, permettra la transposition de cette étude à l’ensemble des enrobés bitumineux.

Recent work has shown the capability of spherical nanoindentation to capture local structure-property relationships in polycrystalline cubic metals by measuring indentation stiffness and yield strength from stress-strain curves as a function of the local microstructure in the indentation zone. However, these protocols capture structure-property relationships at only one level of the material hierarchy (e.g., single grains). Thus it is still very difficult to infer bulk structure-property relationships using these indentation protocols, which is mainly due to a lack of understanding indentation length scale effects and the important role played by structural hierarchy (i.e., unique structural features at different length scales). It is the goal of this work to extend these protocols to systematically study length scale effects of mechanical properties (e.g., indentation stiffness and yield strength) in titanium alloys. Alpha-beta titanium alloys were chosen because they display a rich variety of two phase microstructures and structural hierarchy and are well documented in literature. Firstly, nanoindentation protocols are extended to characterize the elastic and plastic anisotropy of a hexagonally close packed metal (alpha titanium in commercially pure and alloy Ti-6Al-4V) and a two phase microstructure (alpha-beta colony in Ti-6Al-4V). Secondly, spherical microindentation stress-strain protocols are developed and employed to characterize polycrystalline volumes in three titanium alloys (commercially pure, Ti-6Al-4V, and Ti18). The results of these major advances in indentation protocols and systematic study of length scale effects on the mechanical properties in Ti-6Al-4V will be presented and discussed along with applications demonstrating their high throughput nature to rapidly explore alloy development.

Advances in the field of medicine have extended the average human life expectancy worldwide. As a result an increasing number of people will suffer from problems associated with their mineralized tissues and will require orthopedic and dental implants to restore their quality of life. Ideally, implants should have mechanical and structural properties compatible with the original mineralized tissue, and should also promote faster and stronger implant fixation. An improved understanding of the properties of mineralized tissues can help with the improvements of implants. This thesis focuses on improving the understanding of two aspects related to mineralized tissues and implant systems: the mechanical properties of peri-implant bone, and the mechanical, composition and structural properties of dentin and jawbone. Studies have shown that local delivery of alendronate, an anti-osteoporosis drug, enhances new bone formation; however, the effects of the drug on the elastic modulus of new formed bone are unknown. In this study, nanoindentation was used to evaluate and compare the elastic modulus of peri-implant bone with and without the presence of alendronate. To better understand the properties of dentin and jawbone, nanoindentation and qualitative backscattered electron imaging were used to measure their elastic modulus, mineral content and volume fraction, and regression analyses were used to establish correlation between the properties. In this thesis, mineralized tissue samples were collected from an animal study. To study the effects of alendronate on the elastic modulus of peri-implant bone, porous tantalum implants with three different coating treatments were used: non-coated (Ta), calcium phosphate coated (Ta-CaP), alendronate-immobilized-calcium-phosphate coated (Ta-CaP-ALN). The calcium phosphate coatings, with or without alendronate, increased the elastic modulus of peri-implant Ingrown Bone by approximately 22% (3GPa). The addition of alendronate did not significantly increase the elastic modulus of peri-implant. For the study of dentin and jawbone, regression analyses showed that the elastic modulus of dentin is strongly dependent on the porosity and to a lesser extent on the calcium content. The elastic modulus of jawbone and dentin were compared and the elasticmodulus of jawbone was generally higher than that of dentin while the mineral content was lower.

Advances in the field of medicine have extended the average human life expectancy worldwide. As a result an increasing number of people will suffer from problems associated with their mineralized tissues and will require orthopedic and dental implants to restore their quality of life. Ideally, implants should have mechanical and structural properties compatible with the original mineralized tissue, and should also promote faster and stronger implant fixation. An improved understanding of the properties of mineralized tissues can help with the improvements of implants. This thesis focuses on improving the understanding of two aspects related to mineralized tissues and implant systems: the mechanical properties of peri-implant bone, and the mechanical, composition and structural properties of dentin and jawbone. Studies have shown that local delivery of alendronate, an anti-osteoporosis drug, enhances new bone formation; however, the effects of the drug on the elastic modulus of new formed bone are unknown. In this study, nanoindentation was used to evaluate and compare the elastic modulus of peri-implant bone with and without the presence of alendronate. To better understand the properties of dentin and jawbone, nanoindentation and qualitative backscattered electron imaging were used to measure their elastic modulus, mineral content and volume fraction, and regression analyses were used to establish correlation between the properties. In this thesis, mineralized tissue samples were collected from an animal study. To study the effects of alendronate on the elastic modulus of peri-implant bone, porous tantalum implants with three different coating treatments were used: non-coated (Ta), calcium phosphate coated (Ta-CaP), alendronate-immobilized-calcium-phosphate coated (Ta-CaP-ALN). The calcium phosphate coatings, with or without alendronate, increased the elastic modulus of peri-implant Ingrown Bone by approximately 22% (3GPa). The addition of alendronate did not significantly increase the elastic modulus of peri-implant. For the study of dentin and jawbone, regression analyses showed that the elastic modulus of dentin is strongly dependent on the porosity and to a lesser extent on the calcium content. The elastic modulus of jawbone and dentin were compared and the elasticmodulus of jawbone was generally higher than that of dentin while the mineral content was lower.

Advances in the field of medicine have extended the average human life expectancy worldwide. As a result an increasing number of people will suffer from problems associated with their mineralized tissues and will require orthopedic and dental implants to restore their quality of life. Ideally, implants should have mechanical and structural properties compatible with the original mineralized tissue, and should also promote faster and stronger implant fixation. An improved understanding of the properties of mineralized tissues can help with the improvements of implants. This thesis focuses on improving the understanding of two aspects related to mineralized tissues and implant systems: the mechanical properties of peri-implant bone, and the mechanical, composition and structural properties of dentin and jawbone. Studies have shown that local delivery of alendronate, an anti-osteoporosis drug, enhances new bone formation; however, the effects of the drug on the elastic modulus of new formed bone are unknown. In this study, nanoindentation was used to evaluate and compare the elastic modulus of peri-implant bone with and without the presence of alendronate. To better understand the properties of dentin and jawbone, nanoindentation and qualitative backscattered electron imaging were used to measure their elastic modulus, mineral content and volume fraction, and regression analyses were used to establish correlation between the properties. In this thesis, mineralized tissue samples were collected from an animal study. To study the effects of alendronate on the elastic modulus of peri-implant bone, porous tantalum implants with three different coating treatments were used: non-coated (Ta), calcium phosphate coated (Ta-CaP), alendronate-immobilized-calcium-phosphate coated (Ta-CaP-ALN). The calcium phosphate coatings, with or without alendronate, increased the elastic modulus of peri-implant Ingrown Bone by approximately 22% (3GPa). The addition of alendronate did not significantly increase the elastic modulus of peri-implant. For the study of dentin and jawbone, regression analyses showed that the elastic modulus of dentin is strongly dependent on the porosity and to a lesser extent on the calcium content. The elastic modulus of jawbone and dentin were compared and the elasticmodulus of jawbone was generally higher than that of dentin while the mineral content was lower. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

Nanoindentation technique was used to investigate the surface properties of A2 and D2 tool steel subjected to different heat treatments. the mechanical characteristics of these two easily available tool steels were studied based on microstructural images obtained from SEM, the grain growth after heat treatment using X-ray diffraction method and nanoindentation technique. the investigation showed that a single nanoindentation result can explain how heat treatment influences reliability and failure in A2 and D2 tool steels. in this work, the causes and effects of these variations were studied to explain how they influence reliability and failure in A2 and D2 tool steel. Finally, a cube-corner indenter tip was used to determine the fracture toughness of silicon wafer. the emphasis of this research is on how nanoindentation technique is more extensive in material characterization.

Nanoindentation techniques have not been standardized for use on bone tissues, making comparison of bone material properties obtained via nanoindentation across studies difficult and unreliable. This study determined a set of optimal parameter values for thermal drift correction time, dwell time, and loading rate that can be used to obtain accurate and repeatable material properties from human femoral trabecular bone through experimentation and statistical analysis. All testing was conducted using a single nanoindenter on a single trabeculae, with the assumption that material properties within the individual trabeculae were internally consistent. Parameters not of interest during this study, such as ambient temperature, maximum load, and maximum indentation depth were held constant throughout all experiments. Elastic modulus and hardness data were calculated using the Oliver-Pharr technique. The optimal values for these parameters are as follows: 150 seconds for thermal drift correction time, 30 to 60 seconds for dwell time, and 0.4 to 0.8 mN/s for loading rate.

Nanoindentation has a high load resolution, depth sensing capabilities, and can be used to characterize the local mechanical behavior in material systems with heterogeneous microstructures. Recently nanoindentation has been used to extract useful stress-strain curves, primarily in hard materials such as metals and ceramics. To apply these indentation stress-strain methods to polymer composites, we have to first develop analysis techniques for materials that exhibit viscoelasticity. In a lot of current research the viscoelastic material properties are extracted after the material has been deformed enough to initiate plasticity and in some cases the time dependence of the deformation is ignored. This doesn’t give an accurate representation of the material properties of the undeformed sample or the local deformation behavior of the material. This dissertation develops analysis protocols to extract stress-strain curves and viscoelastic properties from the load-displacement data generated from spherical nanoindentation on materials exhibiting time-dependent response at room temperature. Once these protocols are developed they can then be applied, in the future, to study viscoelastic and viscoplastic properties of various mesoscale constituents of composite material systems. These new protocols were developed and tested on polymethyl methacrylate, polycarbonate, low-density polyethylene, and the bio-polymer chitosan. The properties extracted were consistent under different conditions and we were able to produce stress-strain curves for different loading rates and different indenter tip sizes. This dissertation demonstrates that a set of protocols can be used to reliably investigate the mechanical properties and deformation behavior of time-dependent materials using nanoindentation.