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Full-Text Articles in Engineering Science and Materials

Detection Of Surface Cracks In Ferromagnetic Materials By C-Scan Mapping Of Residual Stresses Using Barkhausen Emissions, Neelam Prabhu-Gaunkar, David C. Jiles, G. V. Prabhu Gaunkar Jan 2020

Detection Of Surface Cracks In Ferromagnetic Materials By C-Scan Mapping Of Residual Stresses Using Barkhausen Emissions, Neelam Prabhu-Gaunkar, David C. Jiles, G. V. Prabhu Gaunkar

Electrical and Computer Engineering Publications

Surface cracks can develop in components due to residual stresses, fatigue, stress corrosion cracking, corrosion fatigue, etc, during service exposure. Different non-destructive testing (NDT) methods are employed to detect and monitor such cracks. Magnetic Barkhausen Noise (MBN) analysis is one such technique that is used for in situ examination of microstructural anomalies or stress patterns. In the present work, we study the applicability of MBN for the detection of surface cracks. A part through surface crack was created by controlled fatigue loading of a martensitic stainless steel plate. The surface of the sample was scanned for BN emissions in incremental ...


Tabletop Mechanical Tester, Jamie Dombroski, Brian English, Richard Leffler, Andrew Shirk Jan 2020

Tabletop Mechanical Tester, Jamie Dombroski, Brian English, Richard Leffler, Andrew Shirk

Williams Honors College, Honors Research Projects

The need for hands-on and face-to-face experiences in the engineering classroom is very great. The equations, principles, and concepts can all be learned, but without the visual and tactile application, these don’t always sink in or become concrete. A small-scale tensile test machine was designed, sourced, manufactured, and tested for the purpose of being applied in classroom settings to provide this experience to engineering students. Extensive research was performed concerning tensile machines on the market, the essential elements of which are the load cell, grips, crosshead, extensometer, motor, and frame. The raw materials for the frame were purchased and ...


Jominy Hardenability Tester With In-Situ Heating, Luke Allen Jan 2020

Jominy Hardenability Tester With In-Situ Heating, Luke Allen

Williams Honors College, Honors Research Projects

This project centers on building a Jominy Hardenability tester with In-Situ heating for the manufacturing lab at the University of Akron. A new process and setup will be designed using engineering concepts in order to make the testing more efficient and safer for the teaching and testing of metal hardness. The current Jominy testing setup has efficiency issues within the transfer of specimen from induction heater to testing rig. Our design will simplify the design by creating a test rig that removes the traveling aspect of the specimen which will limit the amount of premature cooling done and will be ...


Effect Of Annealing On The Contact Resistance Of Aluminum On A P-Type Substrate, Shrey Shah, George Patrick Watson Nov 2019

Effect Of Annealing On The Contact Resistance Of Aluminum On A P-Type Substrate, Shrey Shah, George Patrick Watson

Protocols and Reports

Aluminum contacts are widely used to form both ohmic and rectifying contacts. The process to form these contacts involves annealing, thus it is important to study the effect of annealing on the electrical properties of the contacts. Here, we present a way to measure the contact resistance of aluminum contacts formed on a p-type silicon substrate. It was found the contact resistivity decreased by an average of 18%. It was thus found that annealing at 400°C in a forming gas environment improves the electrical properties of aluminum contacts.


Mechanical And Corrosion Properties Of Additively Manufactured Cocrfemnni High Entropy Alloy, Michael A. Melia, Jay D. Carroll, Shaun R. Whetten, Saba N. Esmaeely, Jenifer Locke (Warner), Emma White, Iver E. Anderson, Michael Chandross, Joseph R. Michael, Nicolas Argibay, Eric J. Schindelholz, Andrew B. Kustas Oct 2019

Mechanical And Corrosion Properties Of Additively Manufactured Cocrfemnni High Entropy Alloy, Michael A. Melia, Jay D. Carroll, Shaun R. Whetten, Saba N. Esmaeely, Jenifer Locke (Warner), Emma White, Iver E. Anderson, Michael Chandross, Joseph R. Michael, Nicolas Argibay, Eric J. Schindelholz, Andrew B. Kustas

Ames Laboratory Accepted Manuscripts

This study investigates the mechanical and corrosion properties of as-built and annealed equiatomic CoCrFeMnNi alloy produced by laser-based directed energy deposition (DED) Additive Manufacturing (AM). The high cooling rates of DED produced a single-phase, cellular microstructure with cells on the order of 4 μm in diameter and inter-cellular regions that were enriched in Mn and Ni. Annealing created a chemically homogeneous recrystallized microstructure with a high density of annealing twins. The average yield strength of the as-built condition was 424 MPa and exceeded the annealed condition (232 MPa), however; the strain hardening rate was lower for the as-built material stemming ...


Modeling And Validations Of Control Parameters For Material Extrusion-Based Additive Manufacturing Of Thixotropic Aluminum Alloys., Lars Herhold Aug 2018

Modeling And Validations Of Control Parameters For Material Extrusion-Based Additive Manufacturing Of Thixotropic Aluminum Alloys., Lars Herhold

Electronic Theses and Dissertations

Additive Manufacturing (AM) with metals has been accomplished mainly through powder bed fusion processes. Initial experiments and simulations using Material Extrusion Additive Manufacturing (MEAM) have been performed by various researchers especially using low melting alloys. Recently Stratasys Inc. submitted a patent application for the use of their Material Extrusion technology also called Fused Deposition Modeling (FDM) where they describe the process using thixotropic semi-solid alloys. Currently this process using semi-solid, engineering type alloys such as A356 or THIXALLOY 540 aluminum have not been researched to evaluate the control parameters. This research combines the in-depth knowledge of applying thixotropic semi-solid aluminum ...


Ultrasonic Nondestructive Evaluation Of Metal Additive Manufacturing., Venkata Karthik Nadimpalli May 2018

Ultrasonic Nondestructive Evaluation Of Metal Additive Manufacturing., Venkata Karthik Nadimpalli

Electronic Theses and Dissertations

Metal Additive Manufacturing (AM) is increasingly being used to make functional components. One of the barriers for AM components to become mainstream is the difficulty to certify them. AM components can have widely different properties based on process parameters. Improving an AM processes requires an understanding of process-structure-property correlations, which can be gathered in-situ and post-process through nondestructive and destructive methods. In this study, two metal AM processes were studied, the first is Ultrasonic Additive Manufacturing (UAM) and the second is Laser Powder Bed Fusion (L-PBF). The typical problems with UAM components are inter-layer and inter-track defects. To improve the ...


Effects Of Microstructure And Crystallography On Mechanical Properties Of Cold-Rolled Sae1078 Pearlitic Steel, Y. Liu, C. D. Yang, M. Liu, C. H. Wang, Y. C. Dai, X. Li, Alan M. Russell, C. X. Zhang, Z. H. Zhang, G. H. Cao Jan 2018

Effects Of Microstructure And Crystallography On Mechanical Properties Of Cold-Rolled Sae1078 Pearlitic Steel, Y. Liu, C. D. Yang, M. Liu, C. H. Wang, Y. C. Dai, X. Li, Alan M. Russell, C. X. Zhang, Z. H. Zhang, G. H. Cao

Materials Science and Engineering Publications

The evolution of the microstructure and crystallography in SAE1078 pearlitic steel sheets under different cold-rolling reductions of up to 90% were quantified using transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD). The mechanical properties were determined by tensile testing at room temperature. TEM analysis showed that the pearlite structure was obviously refined with the interlamellar spacing decreasing to about 57 nm at the rolling reduction of 90%. EBSD investigations indicated that the ferrite exhibited a {001}texture in the 90% cold-rolled pearlitic steel. The dislocations were mainly concentrated during cold rolling between the 10% and 70 ...


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 ...


Numerical Simulation Of Multi-Phase Core-Shell Molten Metal Drop Oscillations, Kaushal Sumaria Oct 2017

Numerical Simulation Of Multi-Phase Core-Shell Molten Metal Drop Oscillations, Kaushal Sumaria

Masters Theses

The surface tension of liquid metals is an important and scientifically interesting parameter which affects many metallurgical processes such as casting, welding and melt spinning. Conventional methods for measuring surface tension are difficult to use for molten metals above temperatures of 1000 K. Containerless methods are can be used to measure the surface tension of molten metals above 1000 K. Oscillating drop method is one such method where a levitated droplet is allowed to undergo damped oscillations. Using the Rayleigh’s theory for the oscillation of force-free inviscid spherical droplets, surface tension and viscosity of the sample can be calculated ...


Tem Study Of The Martensitic Phases In The Ductile Dycu And Ycu Intermetallic Compounds, G. H. Cao, C.-G. Oertel, R. Schaarschuch, W. Skrotzki, Alan M. Russell Jun 2017

Tem Study Of The Martensitic Phases In The Ductile Dycu And Ycu Intermetallic Compounds, G. H. Cao, C.-G. Oertel, R. Schaarschuch, W. Skrotzki, Alan M. Russell

Materials Science and Engineering Publications

DyCu and YCu are representatives of the family of CsCI-type B2 rare earth intermetallic compounds that exhibit high room temperature ductility. Structure, orientation relationship, and morphology of the martensites in the equiatomic compounds DyCu and YCu are examined using transmission electron microscopy (TEM). TEM studies show that the martensite structures in DyCu and YCu alloys are virtually identical. The martensite is of orthorhombic CrB-type B33 structure with lattice parameters a = 0.38 nm, b = 1.22 nm, and c = 0.40 nm. (02 (1) over bar) twins were observed in the B33 DyCu and YCu martensites. The orientation relationship of ...


Adsorption Of Salicylhydroxamic Acid On Selected Rare Earth Oxides And Carbonates, Greer Galt Apr 2017

Adsorption Of Salicylhydroxamic Acid On Selected Rare Earth Oxides And Carbonates, Greer Galt

Graduate Theses & Non-Theses

Adsorption behavior of the anionic collector salicylhydroxamic acid (SHA) on a selected group of rare earth oxides (REOs) and carbonates (RECs) was studied via experimental methods and modelling software. Synthetic oxide and carbonate powders of the rare earth elements cerium (Ce), praseodymium (Pr), europium (Eu), and terbium (Tb) were tested for this research. Studies were conducted at different pH levels to analyze the kinetics of collector adsorption onto the oxide and carbonate surfaces in attempts to optimize recovery parameters for commercial flotation processes using SHA. In addition, thermodynamic software StabCal was implemented to compare theoretical adsorption behavior of collectors SHA ...


Tensile Specimen Punch, John Allen Jan 2017

Tensile Specimen Punch, John Allen

All Undergraduate Projects

This project comes from a need to have tensile specimens made for the MET 351, Metallurgy/Materials and Processes, and 426, Applied Strengths of Materials, labs. This punch is designed to be used with an arbor press to create the desired tensile specimen shape out of plastic blanks. The initial concept was suggested by Dr. Craig Johnson. The designs went through many changes, for example getting rid of the sides originally proposed to hold the specimen in place, and modifications to other parts to make them more efficient. Additional parts were also added to the design with the help and ...


Microstructure Control And Correlation To Creep Properties In Grade 91 Steel Weldment After Thermo-Mechanical Treatments And An Fe-30cr-3al Alloy Strengthened By Fe2nb Laves Phase, Benjamin Allen Shassere Dec 2016

Microstructure Control And Correlation To Creep Properties In Grade 91 Steel Weldment After Thermo-Mechanical Treatments And An Fe-30cr-3al Alloy Strengthened By Fe2nb Laves Phase, Benjamin Allen Shassere

Doctoral Dissertations

Type IV cracking in weldments of steel pipes after creep deformation is a concern in modern fossil-fueled power plants. Two possible methods for minimizing or eliminating Type IV cracking will be discussed. The first method alters the initial microstructure of typical Grade 91 steel base metal before welding, while the second provides baseline microstructure characteristics and creep performance of a new alloy that is strengthened by the intermetallic Fe2Nb Laves phase. The initial microstructure of the Grade 91 steel can be controlled by Thermo-Mechanical Treatments, which aids in precipitation of fine (5-10 nm) MX particles in austenite before transformation to ...


A356 Aluminum Alloy, Grain Refining, Modification, Microstructure, Mechanical Properties, Jonghun Yoon Oct 2016

A356 Aluminum Alloy, Grain Refining, Modification, Microstructure, Mechanical Properties, Jonghun Yoon

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Modelling The Evaporation Of Aluminum In Ti–6al–4v Alloy Melted With Electron Beam And Laser, Xuan Wang, Liang Wang, Liang S. Luo, Yan Q. Su, Xin Z. Li, Rui R. Chen, Jing J. Guo, Heng Z. Fu Oct 2016

Modelling The Evaporation Of Aluminum In Ti–6al–4v Alloy Melted With Electron Beam And Laser, Xuan Wang, Liang Wang, Liang S. Luo, Yan Q. Su, Xin Z. Li, Rui R. Chen, Jing J. Guo, Heng Z. Fu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Weld Thermal Simulation Of Crmov With Pwht In Type Iv Region, Bin Xu Oct 2016

Weld Thermal Simulation Of Crmov With Pwht In Type Iv Region, Bin Xu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


The Study On Kinetics Of Metadynamic Recrystallization Of A Nb–V Microalloyed Non-Quenched And Tempered Steel, Li-Wen Zhang, Wen-Fei Shen, Chi Zhang, Ying-Nan Xia, Xin-Hua Shi, Fei Xia Oct 2016

The Study On Kinetics Of Metadynamic Recrystallization Of A Nb–V Microalloyed Non-Quenched And Tempered Steel, Li-Wen Zhang, Wen-Fei Shen, Chi Zhang, Ying-Nan Xia, Xin-Hua Shi, Fei Xia

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Thermal Simulation Of Continuous Casting Solidification Process For A 2205 Duplex Stainless Steel, Xiangru Chen, Qijie Zhai Oct 2016

Thermal Simulation Of Continuous Casting Solidification Process For A 2205 Duplex Stainless Steel, Xiangru Chen, Qijie Zhai

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


The Influence Of Welding Thermal Cycle On Microstructure And Mechanical Properties For 9cr2wvta Steel, Jian Wang, Shanping Lu, Lijian Rong, Dianzhong Li Oct 2016

The Influence Of Welding Thermal Cycle On Microstructure And Mechanical Properties For 9cr2wvta Steel, Jian Wang, Shanping Lu, Lijian Rong, Dianzhong Li

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Fem Simulation Of Laser Shock Processing On Surface Morphology And Residual Stress Field Of Ti-17 Titanium Alloy With Different Laser Impact Times, Rujian Sun, Ying Zhu, Wei Guo, Peng Peng Oct 2016

Fem Simulation Of Laser Shock Processing On Surface Morphology And Residual Stress Field Of Ti-17 Titanium Alloy With Different Laser Impact Times, Rujian Sun, Ying Zhu, Wei Guo, Peng Peng

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Mpfem Simulation On 2d Compaction Of Core–Shell Particulate Composites, Yu Liu, Fen Huang, Peng Han, Xizhong An, Haitao Fu Oct 2016

Mpfem Simulation On 2d Compaction Of Core–Shell Particulate Composites, Yu Liu, Fen Huang, Peng Han, Xizhong An, Haitao Fu

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Thermal Simulation Technology For Solidification Process Of Metals, Qijie Zhai, Honggang Zhong, Renxing Li, Hongxing Zheng Oct 2016

Thermal Simulation Technology For Solidification Process Of Metals, Qijie Zhai, Honggang Zhong, Renxing Li, Hongxing Zheng

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Rapid Grain Boundary Mobility At Ambient Temperatures, Jarrod M. Lund, R Adam Bilodeau, Rebecca K. Kramer Aug 2016

Rapid Grain Boundary Mobility At Ambient Temperatures, Jarrod M. Lund, R Adam Bilodeau, Rebecca K. Kramer

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding and measuring the influence of grain boundaries (planar defects in the crystalline structure of materials) and their motion has become a dominant aspect in materials research, with applications in additive manufacturing, fatigue prevention, and material modeling. However, modeling grain boundaries and grain boundary mobility (GBM) is difficult due to the high temperatures or external stresses, imaging solutions compatible with the material system, and long time-scales required to create measurable experimental results. In this paper, we introduce a novel material system that allows for easy and fast visualization of GBM. A drop of liquid metal eutectic gallium indium (eGaIn) placed ...


Effect Of Microstructure And Crystallography On Sulfide Stress Cracking In Api-5ct-C110 Casing Steel, M. Liu, C. D. Yang, G. H. Cao, Alan M. Russell, Y. H. Liu, X. M. Dong, Z. H. Zhang Aug 2016

Effect Of Microstructure And Crystallography On Sulfide Stress Cracking In Api-5ct-C110 Casing Steel, M. Liu, C. D. Yang, G. H. Cao, Alan M. Russell, Y. H. Liu, X. M. Dong, Z. H. Zhang

Materials Science and Engineering Publications

Microstructure and crystallography have been characterized on an API-5CT-C110 casing steel. Regions near a crack, more distant from a crack, and from specimen with no cracks were analyzed through electron backscatter diffraction (EBSD). A higher proportion of low-angle grain boundaries appeared in the regions near the crack, while regions distant from cracks presented primarily high-angle grain boundaries. The high Kernel Average Misorientation value and more grains with higher Taylor factor emerged in areas beside cracks. The corrosion reactions observed in the cracks would be expected to promote crack growth.


Relationship Between Near-Surface Ultrasonic Shear-Wave Backscatter And Grain Size In Metals, Brady J. Engle, Frank J. Margetan, Leonard J. Bond Jan 2016

Relationship Between Near-Surface Ultrasonic Shear-Wave Backscatter And Grain Size In Metals, Brady J. Engle, Frank J. Margetan, Leonard J. Bond

Aerospace Engineering Conference Papers, Presentations and Posters

Backscattered ultrasonic microstructural noise can be used to estimate grain size in metals. However for normal-incidence immersion measurements the ring-down of the front-wall echo creates a ”dead zone” where backscattered grain noise cannot be quantified. This poses a problem for near-surface grain sizing efforts. In this paper we explore the use of mode-converted 45-degree shear waves for near-surface grain sizing using a water immersion setup. We discuss how to accurately relate grain noise arrival time with depth of sound penetration in the metal. Then for a set of Ni-alloy specimens having near-equiaxed microstructures we correlate various backscattered noise attributes with ...


Material Property Relationships For Pipeline Steels And The Potential For Application Of Nde, Lucinda Smart, Leonard J. Bond Jan 2016

Material Property Relationships For Pipeline Steels And The Potential For Application Of Nde, Lucinda Smart, Leonard J. Bond

Aerospace Engineering Conference Papers, Presentations and Posters

The oil and gas industry in the USA has an extensive infrastructure of pipelines, 70% of which were installed prior to 1980, and almost half were installed during the 1950s and 1960s. Ideally the mechanical properties (i.e. yield strength, tensile strength, transition temperature, and fracture toughness) of a steel pipe must be known in order to respond to detected defects in an appropriate manner. Neither current in-ditch methods nor the ILI inspection data have yet determined and map the desired mechanical properties with adequate confidence. In the quest to obtain the mechanical properties of a steel pipe using a ...


Effect Of Time Delay Between Etching And Adhesive Bonding (“Outlife” Time) On Lap-Shear Strength Of Aluminum Alloys Using Environmentally-Friendly P2 Etch, Josh Barkhimer, Matthew Erich, Gokul Nair Jun 2015

Effect Of Time Delay Between Etching And Adhesive Bonding (“Outlife” Time) On Lap-Shear Strength Of Aluminum Alloys Using Environmentally-Friendly P2 Etch, Josh Barkhimer, Matthew Erich, Gokul Nair

Materials Engineering

Raytheon Company currently uses a Forest Products Laboratory (FPL) paste etchant for preparing aluminum surfaces for adhesive bonding, and FPL is a source of hazardous hexavalent chromium. The goal of this study was to evaluate a less-toxic P2 paste etchant as a possible replacement. Coupons of 2024-T3, 6061-T6, and 7075-T6 grades of aluminum alloy were solvent-degreased, abrasively cleaned, and etched at room temperature using P2 paste following a strict protocol adopted from Raytheon. Coupons were then left exposed to air for assigned time intervals (or “outlife” times) of 0, 1, 4, 8, 16, and 63 or 72 hours. The aluminum ...


Influence Of Spatial Variations Of Railroad Track Stiffness And Material Inclusions On Fatigue Life, Celestin Nkundineza Jan 2015

Influence Of Spatial Variations Of Railroad Track Stiffness And Material Inclusions On Fatigue Life, Celestin Nkundineza

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Railroad transportation is very important for economic growth and effective maintenance is one critical factor for its economic sustainability. The high repetitive forces from a moving railcar induce cyclic stresses that lead to rail bending and potential deterioration due to fatigue crack initiation and propagation. Previous research for prediction of fatigue life has been done under the assumptions of a uniform track bed and a homogeneous rail. However the spatial variation of the track stiffness is expected to increase the maximum stresses in the rail and, therefore, accelerate the fatigue process. The research described in this dissertation is focused on ...


The Examination Of Stress Corrosion Cracking In High Strength Carbon Steel Through Combined Mechanical-Electrochemical Testing, Jacob Sines Jan 2015

The Examination Of Stress Corrosion Cracking In High Strength Carbon Steel Through Combined Mechanical-Electrochemical Testing, Jacob Sines

Williams Honors College, Honors Research Projects

Through the analysis of materials and environments seen in industry a better understanding of the fundamentals behind degradation mechanisms can be observed. The scope of this project was to better understand the fundamentals behind the degradation of high strength pipeline steels in a lab setting to simulate an environment seen in industry. Specifically the degradation mechanisms of high and nearly neutral pH stress corrosion cracking were examined in environments that simulated oil and gas pipelines buried in soil. Experimentation was carried out utilizing X65 carbon steel specimen, a Gamry potentiostat, a CORTEST proof ring, a CORTEST slow strain rate machine ...