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Full-Text Articles in Engineering

Predicting Hardness Of Friction Stir Processed 304l Stainless Steel Using A Finite Element Model And A Random Forest Algorithm, Tyler Alan Mathis Aug 2019

Predicting Hardness Of Friction Stir Processed 304l Stainless Steel Using A Finite Element Model And A Random Forest Algorithm, Tyler Alan Mathis

Theses and Dissertations

Friction stir welding is an advanced welding process that is being investigated for use in many different industries. One area that has been investigated for its application is in healing critical nuclear reactor components that are developing cracks. However, friction stir welding is a complicated process and it is difficult to predict what the final properties of a set of welding parameters will be. This thesis sets forth a method using finite element analysis and a random forest model to accurately predict hardness in the welding nugget after processing. The finite element analysis code used and ALE formulation that enabled ...


The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, David Kok Apr 2019

The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, David Kok

Scholar Week 2016 - present

The Molten Salt Reactor (MSR) has been identified as a promising candidate to replace aging nuclear reactors around the world. However, a suitable combination of molten salt and container material needs to be found in order to reduce the potential for corrosion in the MSR before it can be considered commercially viable. FLiNaK molten salt and the nickel-based alloy Hastelloy N have been identified as prime candidates for this function, but the severity of FLiNaK corrosion in Hastelloy N requires additional study before this combination can be used in the operation of a MSR. In this study, Hastelloy N samples ...


The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, David Kok Jan 2019

The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, David Kok

Honors Program Projects

The desire to reduce pollution caused by electricity production has led to a call for the replacement of conventional fossil fuel power plants. In order to fulfill this goal, a large amount of new nuclear reactors is required, and this provides the opportunity to put new and innovative reactor designs into production. The Molten Salt Reactor (MSR) is one of the most promising concepts, but a suitable combination of molten salt and container material needs to be found to reduce the potential for corrosion before the concept can be put into production. FLiNaK molten salt and the nickel-based alloy Hastelloy ...


Custom Foot Prosthetic: Diabetic Care, Chandler Streuli Jan 2019

Custom Foot Prosthetic: Diabetic Care, Chandler Streuli

All Undergraduate Projects

Across the United States there are people every day who lose their toes to diabetes or to loss of circulation within their legs. The problem becomes building a more cost effective and efficient prosthetic for these individuals. The prosthetics that are used for medical purposes are often costly, especially without the help of insurance. The new prosthetic was designed to be taken in and out of shoes so that it is fast and easy for the user to move the device from shoe to shoe. The manufacturing method for this project was using a 3D printer to build the initial ...


Nanoindentation Characterization On Local Plastic Response Of Ti-6al-4v Under High-Load Spherical Indentation, Yan Wen, Lechun Xie, Zhou Wang, Liqiang Wang, Weijie Lu, Laichang Zhang Jan 2019

Nanoindentation Characterization On Local Plastic Response Of Ti-6al-4v Under High-Load Spherical Indentation, Yan Wen, Lechun Xie, Zhou Wang, Liqiang Wang, Weijie Lu, Laichang Zhang

ECU Publications Post 2013

After high-load spherical indentation treatment, the variations of hardness on the plastic zone of Ti-6Al-4V were investigated via nanoindentation method. The hardness within the center of plastic zone was measured by nanoindenter, and the magnitude decreased gradually along the depth, which were caused by the different extent of plastic deformation under the residual imprint. The microstructure of indentation were observed using scanning electron microscope (SEM) before and after surface etching, and the results showed that the microhardness revealed the average hardness of α and β phases of Ti-6Al-4V. The maximum hardness reached 6.438 GPa in the depth of 132 ...


Beta-Type Ti-Nb-Zr-Cr Alloys With Large Plasticity And Significant Strain Hardening, Syed F. Jawed, Chirag D. Rabadia, Y. J. Liu, L. Q. Wang, Y. H. Li, X. H. Zang, Laichang C. Zhang Jan 2019

Beta-Type Ti-Nb-Zr-Cr Alloys With Large Plasticity And Significant Strain Hardening, Syed F. Jawed, Chirag D. Rabadia, Y. J. Liu, L. Q. Wang, Y. H. Li, X. H. Zang, Laichang C. Zhang

ECU Publications Post 2013

A series of Ti-25Nb-8Zr-xCr (x = 0, 2, 4, 6, 8 wt%) alloys were designed based on DV-Xα cluster method and e=a-Δr diagram with an anticipation to obtain high plasticity and significant strain hardening. The designed alloys were produced through cold crucible levitation melting technique in order to effectively investigate their micro-structures and mechanical properties. The addition of Cr significantly enhances the β stability in the microstructures of the Ti-25Nb-8Zr-xCr alloys. Both yield strength and hardness of the studied alloys increase due to the effect of solid-solution strengthening. By contrast, the plasticity, maximum strength and strain hardening rate are influenced ...


Solid Solution Strengthened Fe Alloys, Sidharth Krishnamoorthi, Ruizhe Su, Yifan Zhang, Xinghang Zhang Aug 2018

Solid Solution Strengthened Fe Alloys, Sidharth Krishnamoorthi, Ruizhe Su, Yifan Zhang, Xinghang Zhang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Iron (Fe)-based alloys (such as steel) are widely used structural materials in industry. Numerous methods have been applied to improve their mechanical properties. In this study, we used a technique know as magnetron sputtering to deposit various Fe-based binary alloy coatings to investigate the influence of solutes on solid solution hardening. Several factors contribute to the solid solution hardening of the alloys, such as composition, atomic radius, modulus, and lattice parameter. After preliminary calculations and analysis, we selected several solutes, including molybdenum (Mo), niobium (Nb), and zirconium (Zr). The compositions of solutes were varied to be 2.5, 5 ...


Defect Growth Characterization In Modern Rail Steel, Sena Kizildemir May 2018

Defect Growth Characterization In Modern Rail Steel, Sena Kizildemir

Theses and Dissertations

This thesis investigates the fatigue characterization of modern head-hardened rails, with a specific focus on detail (i.e. transverse) fracture. This study provides necessary information to determine a safe and economically viable rail inspection interval.Safe inspection interval has previously been established for legacy, i.e. non-head-hardened rails. The head hardening process, which evolved over the past several decades, has been designed to improve rail wear resistance by increasing hardness. Unfortunately, increasing hardness, which is related to strength, typically results in reduction of toughness and fatigue life. This means that while improved wear resistance can extend the wear life of ...


Analysis Of Ni And Fe-Based Alloys For Turbine Seal Ring Applications, Dawei She Mar 2018

Analysis Of Ni And Fe-Based Alloys For Turbine Seal Ring Applications, Dawei She

Graduate Theses and Dissertations

Metal sealing rings have been used widely in compressors, turbines and hydraulic devices. Such rings can extend out due to elasticity, and keep close contact with the valve wall, resulting in the formation of a functional seal under pressure. In this project, the failure of metal sealing rings is considered. Sealing component failure due to stress relaxation can threaten the safety of the whole steam turbine. The object of this study was to examine the stress relaxation response and corresponding changes in microstructure of metal sealing rings used in nuclear steam turbine under high temperature and applied stress. The two ...


Raman Spectroscopy Of The Skeleton Of The Coral Acropora Cervicornis, Zachary C. Shepard Jan 2018

Raman Spectroscopy Of The Skeleton Of The Coral Acropora Cervicornis, Zachary C. Shepard

Honors Undergraduate Theses

Coral reefs are an important element of marine ecosystem that are critical to maintain a healthy environment. Unfortunately, in recent years coral reefs are doing poorly and many in parts of the ocean are simply dying. Therefore, study of coral’s structural response to external loads could answer what will happen with their structures, while they exhibit different types of loading. Therefore, the proposition of using in-situ micro-Raman spectroscopy to study skeletons of Acropora cervicornis was used. Coral skeleton samples I subjected to mechanical loading studied their vibrational properties by exciting the material with 532nm visible light. A uniaxial compressive ...


Effect Of Ultrasonic Treatment On The Microstructure And Mechanical Properties Of Al6061 And Composite, Ana S. Exime Nov 2017

Effect Of Ultrasonic Treatment On The Microstructure And Mechanical Properties Of Al6061 And Composite, Ana S. Exime

FIU Electronic Theses and Dissertations

In this study, the effect of ultrasonic treatment (UST) parameters such as amplitude, sonication time, and melt temperature on microstructure and microhardness of Al 6061 alloy is evaluated. The effect of UST on the dispersion of tungsten disulfide (WS2) and carbon nanotubes (CNT) as reinforcement particles in Al 6061 during casting is also studied. The cast Al 6061 with UST demonstrated 32% grain size reduction and 8% increase in the microhardness for optimum processing conditions. The cavitation process induced by UST is responsible for the refinement in microstructure and increase of hardness by enhancing the degassing and nucleation process ...


Failure Analysis Of High Nickel Alloy Steel Seal Ring Used In Turbomachinery, Wenbo Wang Mar 2017

Failure Analysis Of High Nickel Alloy Steel Seal Ring Used In Turbomachinery, Wenbo Wang

Graduate Theses and Dissertations

The system of upper high nickel alloying steel seal ring and lower high nickel alloying steel seal ring, installed in the grooves of turbine, can extend out and fit with the wall of valve cage, resulting in forming a good seal under the pressure. In the project, the failure steel seal ring is considered. This situation had threatened the safety of the whole steam turbine system. The purpose of this study is to identify the failure cause of the steel seal ring used in nuclear steam turbines. New high nickel steel alloy seal ring was compared with the failed seal ...


Displaced Hardness Peak Phenomenon In Heat-Affected Zone Of Welded Quenched And Tempered Em812 Steel, Druce P. Dunne, W Pang Jan 2017

Displaced Hardness Peak Phenomenon In Heat-Affected Zone Of Welded Quenched And Tempered Em812 Steel, Druce P. Dunne, W Pang

Faculty of Engineering and Information Sciences - Papers: Part A

Investigations of microstructural and hardness gradients in the heat-affected zone (HAZ) of quenched and tempered (Q&T) steels have indicated that peak hardness does not occur in the grain-coarsened heat-affected zone (GCHAZ) adjacent to the fusion boundary, which is typical of ferritic steels, but corresponds more closely to the grain-refined region (GRHAZ). This phenomenon, the displaced hardness peak (DHP) effect, is considered to arise when the hardenability of the steel is high enough to result in the same microstructure in the GC and GR heat-affected zones, except for significant refinement of the microstructure of the GRHAZ, which increases the hardness ...


Effect Of Sintering Temperature On Microstructure, Corrosion Behavior, And Hardness Of Nanocrystalline Al-5at.%Ni And Al-5at.%V Alloys, Matthew G. Wachowiak Jan 2017

Effect Of Sintering Temperature On Microstructure, Corrosion Behavior, And Hardness Of Nanocrystalline Al-5at.%Ni And Al-5at.%V Alloys, Matthew G. Wachowiak

Williams Honors College, Honors Research Projects

The purpose of this project was to investigate thermal stability of high energy ball milled Al-5at.%Ni and Al-5at.%V alloys. Characterization was done by analyzing grain size and solid solubility. Samples were created using high energy ball milling, cold compaction to 3 GPa, and sintering from 100 °C to 500 °C at 100 °C increments, as well 450 °C and 614 °C. Microstructure, mechanical properties, and corrosion properties were determined using scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, hardness testing, and cyclic potentiodynamic polarization. Vickers hardness of Al-5at.%Ni decreased with increasing temperature. For Al-at.%V, hardness ...


Indentation Behavior Of Superelastic Hard Carbon, Olga Chernogorova, Ekaterina Drozdova, Iraida Ushakova, Evgenii Ekimov, Vicente Benavides, Aleksander Soldatov Oct 2016

Indentation Behavior Of Superelastic Hard Carbon, Olga Chernogorova, Ekaterina Drozdova, Iraida Ushakova, Evgenii Ekimov, Vicente Benavides, Aleksander Soldatov

Nanomechanical Testing in Materials Research and Development V

Supererlastic hard carbon particles up to 1 mmin size were produced by fullerene collapse upon high-pressure high-temperature treatment with simultaneous sintering of metal-matrix composite materials (CM) reinforced by such particles. The hardness of carbon particles can be varied in a wide range by changing the parameters of their structure, which consists of curved graphene planes or their packets of different sizes. Such carbon phase was called “nanoclusterd graphene phase” (NGP) [1]. The properties of the carbon particles were controlled by changing treatment pressure (5 and 8 GPa) and temperature (1100-1800 K), composition of parent fullerites (C60 or C60/70), and ...


Growing Larger: Scaling Up During Spark Plasma Sintering Of High– Temperature Ceramics, Oleg Vasylkiv Mar 2016

Growing Larger: Scaling Up During Spark Plasma Sintering Of High– Temperature Ceramics, Oleg Vasylkiv

Electric Field Assisted Sintering and Related Phenomena Far From Equilibrium

Recently, extensive efforts were made towards investigation and development of spark plasma sintering (SPS) as a promising technique for rapid densification of ceramics at relatively low temperatures. In this respect, SPS was used for various processes and materials including fabrication of bulk metals and ceramics and their composites. Furthermore, this ‘low temperature’ processing allowed consolidation of ceramics with strong covalent bonding to the full density. However, significant gap exists between the technological and fabrication achievements to the fundamental understanding of the SPS mechanisms. This gap is due to the complexity of the thermal, electrical and mechanical processes that may be ...


Cryogenic Processing Of Al 7050-T7451 Alloy For Improved Surface Integrity, Bo Huang Jan 2016

Cryogenic Processing Of Al 7050-T7451 Alloy For Improved Surface Integrity, Bo Huang

Theses and Dissertations--Mechanical Engineering

Al 7050-T7451 alloy with good combinations of strength, stress corrosion cracking resistance and toughness, is used broadly in the aerospace/aviation industry for fatigue-critical airframe structural components. However, it is also considered as a highly anisotropic alloy as the crack growth behavior along the short transverse direction is very different from the one in the long transverse direction, due to the inhomogeneous microstructure with the elongated grains distributed in the work material used in the sheet/plate applications. Further processes on these materials are needed to improve its mechanical and material properties and broaden its applications.

The material with ultra-fine ...


Laser Waterjet Heat Treatment On Super-Hard Materials, Jingnan Zhao Jan 2016

Laser Waterjet Heat Treatment On Super-Hard Materials, Jingnan Zhao

Graduate Theses and Dissertations

The use of the hybrid laser waterjet heat (LWH) treatment process to develop super-hard materials is a new field of research that has the potential to develop materials with hardness characteristics that compare with or exceed that of diamond. The research presented in this dissertation investigated the hardness improvement mechanism of boron nitride (BN) materials by investigating the optimization of LWH process parameters and studying the microstructural refinement of BN materials. The study of the LWH system parameters investigated the relationship between LWH system parameters and the BN materials’ hardness change ratio. Upon the study, the optimal LWH system parameters ...


Ultrahard Polycrystalline Cubic Boron Nitride Composite Through Hybrid Laser/Waterjet Heat (Lwh) Treatment, Jingnan Zhao, Pranav Shrotriya Jan 2016

Ultrahard Polycrystalline Cubic Boron Nitride Composite Through Hybrid Laser/Waterjet Heat (Lwh) Treatment, Jingnan Zhao, Pranav Shrotriya

Mechanical Engineering Publications

Ultra-hard materials that are chemically inert and thermally stable at high temperatures are desirable for enhancing machining and wear performance in demanding chemical and thermal environments. Single and polycrystalline diamonds are the hardest tool materials; however, at high temperatures, diamond reacts with ferrous alloys, losing its chemical inertness and thermal stability. In contrast, cubic boron nitride (cBN) has exceptional chemical and thermal stability but has much lower hardness (35-45 GPa). Increasing the hardness of BN is expected to fill the property gap in state-of-the-art tool materials as shown and to generate huge industrial interest for meeting the stringent design requirements ...


Nanoindentation Cartography In Al/Al-Cu-Fe Composites: Correlation Between Chemical Heterogeneities And Mechanical Properties, Christophe Tromas, Aurelie Joseph, Veronique Gauthier, Anne Joulain, Sylvain Dubois, Joel Bonneville, Dominique Evidi, Jean-Phillippe Monchoux Oct 2015

Nanoindentation Cartography In Al/Al-Cu-Fe Composites: Correlation Between Chemical Heterogeneities And Mechanical Properties, Christophe Tromas, Aurelie Joseph, Veronique Gauthier, Anne Joulain, Sylvain Dubois, Joel Bonneville, Dominique Evidi, Jean-Phillippe Monchoux

Nanomechanical Testing in Materials Research and Development V

During the last two decades, nanoindentation testing has become a commonly used technique for measuring surface mechanical properties such as hardness or elastic modulus. With devices equipped with a motorized X-Y table, it is now possible to perform large regular nanoindentation arrays in order to make an accurate statistics of the mechanical properties. This method is particularly interesting to study heterogeneous materials. The statistical analysis, associated to mathematical deconvolution methods allows identifying the properties of each individual phase. Furthermore, hardness or elastic modulus maps can be then established and compared to other local properties such as microstructure, crystallographic orientation or ...


High Temperature Nanoindentation Testing Of Amorphous Silicon Carbonitride Thin Films, Radim Ctvrtlik, Marwan Al-Haik, Valeriy Kilikovsky Oct 2015

High Temperature Nanoindentation Testing Of Amorphous Silicon Carbonitride Thin Films, Radim Ctvrtlik, Marwan Al-Haik, Valeriy Kilikovsky

Nanomechanical Testing in Materials Research and Development V

The mechanical properties of amorphous silicon carbonitride (SiCxNy) films with various nitrogen content (y = 0-40 at.%) were investigated in-situ at elevated temperatures up to 650 °C in inert atmosphere. The hardness and elastic modulus were evaluated using depth sensing nanoindentation with cubic boron nitride Berkovich indenter. Both the sample and indenter were separately heated during the experiments to temperatures 300, 500 and 650 °C. Short duration high temperature creep (1200 s) of the films was also investigated. The results revealed that the room temperature hardness and elastic modulus decline with the increase of the nitrogen content. Furthermore ...


An Investigation Of Nanoparticles Addition On Solidification Kinetics And Microstructure Development Of Tin–Lead Solder, D. Lin, S. Liu, T. Guo, Guo-Xiang Wang, T. Srivatsan, M. Petraroli Apr 2015

An Investigation Of Nanoparticles Addition On Solidification Kinetics And Microstructure Development Of Tin–Lead Solder, D. Lin, S. Liu, T. Guo, Guo-Xiang Wang, T. Srivatsan, M. Petraroli

Dr. Guo-Xiang Wang

High strength solders can be engineered by adding trace amounts of nanopowders into solder paste. An experimental study was conducted for a better understanding of the solidification kinetics and microstructure development of such nano-composite tin–lead solders. The composite solder pastes were prepared by mechanically mixing nanopowders of either copper or TiO2 with tin–lead powders (tens of microns in size). Solidification experiments of the composite solders were performed in an aluminum crucible with temperature variation during cooling and solidification being measured. For the titanium dioxide (TiO2) nanopowders-reinforced composite solders, the test data reveals the occurrence of melt ...


Synthesis And Characterization Of Nano-Composite Lead-Free Solder, D. Lin, C. Kuo, T. Srivatsan, M. Petraroli, Guo-Xiang Wang Apr 2015

Synthesis And Characterization Of Nano-Composite Lead-Free Solder, D. Lin, C. Kuo, T. Srivatsan, M. Petraroli, Guo-Xiang Wang

Dr. Guo-Xiang Wang

A series of experiments conducted on a lead-free eutectic solder (Sn-3.5%Ag) have shown that addition of trace amounts of nanometer-sized particles does have an influence on mechanical properties of materials. In this study, three different types of nanoparticles (copper, nickel and iron) were chosen as the reinforcing candidate. For each particulate reinforcement the reflow process was performed under identical cooling conditions. Addition of trace amounts of nano-particles alters the kinetics governing solidification of the composite solder paste while concurrently exerting an influence on microstructural development, particularly the formation and presence of second phases in the solidified end product ...


High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas Wyrobek, Oden Warren, Jason Hattrick-Simpers, Olubenga Famodu, Ichiro Takeuchi Mar 2015

High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas Wyrobek, Oden Warren, Jason Hattrick-Simpers, Olubenga Famodu, Ichiro Takeuchi

Jason R. Hattrick-Simpers

We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memoryalloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memoryalloy composition region, located around the Heusler composition (Ni2MnAl), was found to display significant departure in these mechanical properties from the rest of the composition spread. In particular, the modulus and the hardness values are lower for the martensite region than those of the rest of the ...


An Investigation Of Friction Stir Welding Parameter Effects On Post Weld Mechanical Properties In 7075 Aa, Steven B. Dickson Mar 2015

An Investigation Of Friction Stir Welding Parameter Effects On Post Weld Mechanical Properties In 7075 Aa, Steven B. Dickson

Theses and Dissertations

The effects of weld temperature, travel speed, and backing plate thermal diffusivity on themechanical properties of a weld have been studied. A face centered cubic experiment of designwas completed in which the response variables were yield strength, minimum hardness in the HAZ, and charpy impact toughness. Three models were created from the data gathered usinga stepwise regression in order to see the effects of each parameter. For the yield strength andminimum hardness it was found that only travel speed and backing plate thermal diffusivities werestatistically significant to the properties. The charpy impact toughness saw that all three parameterswere statistically significant ...


Alternative Methods To Determine The Elastoplastic Properties Of Sintered Hydroxyapatite From Nanoindentation Testing Feb 2015

Alternative Methods To Determine The Elastoplastic Properties Of Sintered Hydroxyapatite From Nanoindentation Testing

Faculty of Engineering University of Malaya

This study introduces alternative methods to determine the elastoplastic properties of bovine-derived Hydroxyapatite (HA) porous bone graft through a set of nanoindentation tests with a Berkovich indenter. Generally, experimental data obtained from nanoindentation tests are force displacement, hardness and elastic modulus. However, to determine plastic properties such as strength coefficient and work hardening exponent of bovine HA, analytical or inverse finite element models are required. In this paper, the effect of sintering temperature on these properties of HA is studied for the range of 1000-1400 degrees C. The direct and inverse Finite Element (FE) simulation models for nanoindentation tests were ...


Nanomechanical Characterization Of Cavity Growth And Rupture In Hydrogen-Implanted Single-Crystal Batio3., Young-Bae Park, Patrick Nardi, Xiaodong Li, Harry A. Atwater Feb 2015

Nanomechanical Characterization Of Cavity Growth And Rupture In Hydrogen-Implanted Single-Crystal Batio3., Young-Bae Park, Patrick Nardi, Xiaodong Li, Harry A. Atwater

Xiaodong Li

A thermodynamic model of cavitynucleation and growth in ion-implanted single-crystal BaTiO3 layer is proposed, and cavity formation is related to the measured mechanical properties to better understand hydrogen implantation-induced layer transfer processes for ferroelectric thin films. The critical radius for cavitynucleation was determined experimentally from blistering experiments performed under isochronal anneal conditions and was calculated using continuum mechanical models for deformation and fracture, together with thermodynamic models. Based on thermodynamic modeling, we suggest that cavitiesgrow toward the cracking criteria at a critical blister size whereupon gas is emitted from ruptured cavities. The main driving force for layer splitting is the ...


Investigating The Surface Tribology Of Roller-Burnished Polymer Using The Fuzzy Rule-Based Approach Jan 2015

Investigating The Surface Tribology Of Roller-Burnished Polymer Using The Fuzzy Rule-Based Approach

Faculty of Engineering University of Malaya

Burnishing is specified as the plastic deformation cold working process applied as surface treatment and smoothing following machining to obtain a superior surface roughness finish. The present experimental study was carried out on roller-burnished polyurethane using a roller burnishing tool. An analysis was done to investigate the effect of burnishing depth, speed, feed rate, and roller width on the surface roughness of the polymer workpiece. Roughness (R-a) prediction was achieved with a fuzzy rule-based system. The results indicate 95% accuracy between the fuzzy predicted roughness values and experimental results. Link to Full-Text Articles : www.tandfonline.com/doi/abs/10.1080 ...


Lasers Processing Of Ultra-Hard Materials, Ammar Abdulghani Melaibari Jan 2015

Lasers Processing Of Ultra-Hard Materials, Ammar Abdulghani Melaibari

Graduate Theses and Dissertations

Laser processing of ultra-hard materials is a relatively new field that have the potential to improve variety of products and different industries. This dissertation explores specific new development in this field through three main subjects: laser machining, laser deposition of thin film, and laser treatment. In laser machining of ultra-hard material, controlled crack propagation mechanism -as opposed to the typical ablation mechanism- was investigated, and micromachining of ultra-hard thin film was also observed. For the laser deposition of ultra-hard thin film, designing new microstructured materials was explored, and the utilization of the inherent particulate formation associated with the pulsed laser ...


Nanomechanical And Morphological Characterization Of Tungsten Trioxide (Wo3) Thin Films Grown By Atomic Layer Deposition, M. A. Mamun, K. Zhang, H. Baumgart, A. A. Elmustafa Jan 2015

Nanomechanical And Morphological Characterization Of Tungsten Trioxide (Wo3) Thin Films Grown By Atomic Layer Deposition, M. A. Mamun, K. Zhang, H. Baumgart, A. A. Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

This study investigates the nanomechanical properties and surface morphology of tungsten oxide WO3thin films deposited on p-type Si(100) substrates using atomic layer deposition (ALD) technology with 2000 ALD deposition cycles at a growth temperature of 300°C and annealed at different temperatures. The samples were further furnace annealed at 500, 600 and 700°C for 60 min. The influence of the deposition process on the structure and properties of the WO3 films is discussed, presented and correlated to the characteristic features of the ALD technique. The results depict significant difference in the hardness and modulus measurements ...