Metallurgy Commons^™

Research And Development Of Powder Brazing Filler Metals For Diamond Tools: A Review, Fei Long, Peng He, Dusan P. Sekulic

Mechanical Engineering Faculty Publications

Powder brazing filler metals (PBFMs) feature a number of comparative advantages. Among others, these include a low energy consumption, an accurate dosage, a good brazeability, a short production time, and a high production efficiency. These filler metals have been used in the aerospace, automobile, and electric appliances industries. The PBFMs are especially suitable for diamond tools bonding, which involves complex workpiece shapes and requires accurate dosage. The recent research of PBFMs for diamond tools is reviewed in this paper. The current applications are discussed. The CuSnTi and Ni-Cr-based PBFMs have been the two commonly used monolayer PBFMs. Thus, the bonding …

Analysis Of Surface Integrity In Machining Of Aisi 304 Stainless Steel Under Various Cooling And Cutting Conditions, F. Klocke, B. Döbbeler, S. Lung, S. Seelbach, Ibrahim S. Jawahir

Institute for Sustainable Manufacturing Faculty Publications

Recent studies have shown that machining under specific cooling and cutting conditions can be used to induce a nanocrystalline surface layer in the workspiece. This layer has beneficial properties, such as improved fatigue strength, wear resistance and tribological behavior. In machining, a promising approach for achieving grain refinement in the surface layer is the application of cryogenic cooling. The aim is to use the last step of the machining operation to induce the desired surface quality to save time-consuming and expensive post machining surface treatments. The material used in this study was AISI 304 stainless steel. This austenitic steel suffers …

The Incorporation Of Graphene To Lithium Cobalt Oxide As A Cathode To Improve The Performance Of Lithium Ion Batteries, Kenan Wang

Graduate Theses and Dissertations

One of the objectives of this thesis work was to investigate the cathode performance of lithium cobalt oxide (LiCoO2) incorporated with graphene powder in lithium ion batteries (LIBs). Graphene powder was incorporated into cathode materials to enhance the performance of LIBs. The other objective was to impede the construction of a solid electrolyte interphase (SEI) sheet using graphene sheet coating on its cathode.

The results of this work show that adding graphene powder improved the performance of LiCoO¬2 as a cathode material. With the incorporation of different weight percentages of graphene powder, the LiBs showed distinct changes in their charging …

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 …

Self-Assembled Barium Titanate Nanoscale Films By Molecular Beam Epitaxy, Timothy Allen Morgan

Graduate Theses and Dissertations

One challenge of investigating ferroelectrics at the nanoscale has been controlling the stoichiometry during growth. Historically, the growth of barium titanate (BaTiO3) by molecular beam epitaxy has relied on a growth technique called shuttered RHEED. Shuttered RHEED controls the stoichiometry of barium titanate through the precise deposition of alternating layers of BaO and TiO2. While this approach has achieved 1% control of stoichiometry, finding self-limiting mechanisms to lock-in stoichiometry has been the focus of the growth community. The Goldschmidt tolerance factor predicts an unstable perovskite when barium sits in the titanium lattice site. The BaO-TiO2 phase diagram predicts a low-solubility …

Fabrication And Characterization Of Graphene Based 2d Materials For Supercapacitors, Anishkumar Manoharan

Graduate Theses and Dissertations

Supercapacitors have attracted a lot attention due to their efficient energy storage. In comparison to batteries, supercapacitors have high capacitance, energy, and power densities per unit mass than conventional capacitors. Carbon based materials are most promising in supercapacitor application due to their outstanding physical and electrochemical behavior. In this work, a facile method to synthesize a nanocomposite electrode consisting of annealed carbon from carbon ink and MoS2 was demonstrated. Effects of various aqueous and solid electrolytes were studied. It was found that the nanocomposite electrode with 10% MoS2 and 1M Na2SO4 as the aqueous electrolyte tested using the three electrode …

Evolution Of Mg Az31 Twin Activation With Strain: A Machine Learning Study, Andrew D. Orme

Undergraduate Honors Theses

Machine learning is being adopted in various areas of materials science to both create predictive models and to uncover correlations which reveal underlying physics. However, these two aims are often at odds with each other since the resultant predictive models generally become so complex that they can essentially be described as a black box, making them difficult to understand. In this study, complex relationships between microstructure and twin formation in AZ31 magnesium are investigated as a function of increasing strain. Supervised machine learning is employed, in the form of J-48 decision trees. In one approach, strain is incorporated as an …

Characterization Of Process Induced Defects In Laser Powder Bed Fusion Processed Alsi10mg Alloy, Edward Stugelmayer

Graduate Theses & Non-Theses

Additive manufacturing using laser powder bed fusion (AM-LPBF) methods have recently experienced rapid growth and development, having the potential to replace manufacturing by plastic deformation, precision machining, or casting. AM offers advantages such as the freedom to design highly complex geometries, time and cost savings through material usage efficiency and shortened production cycles, and the potential for improved mechanical properties. Process induced defects, however, result in degradation and scattering of mechanical properties and hinder the widespread adoption of AM-LPBF in industry. This investigation focuses on the effects of varying energy density and build orientation on the evolution of process induced …

Investigations Of Solid-State Sintering Behavior Of Binary Refractory Metal Oxide Systems, Maureen Chorney

Graduate Theses & Non-Theses

Refractory metals are commonly alloyed for improved corrosion resistance, thermal stability, and strength. In service, these alloys form highly stable oxides under mildly oxidizing conditions at relatively low temperatures. In order to recycle these materials, high temperature electrochemical processing is required to reduce the refractory metal oxides. To abet experimental evaluation of the electrochemical reduction process under development at the Idaho National Laboratory, binary mixtures of selected refractory metal oxide powders were sintered to produce cathode pellets, which could be suspended in the molten salt electrolyte during reduction experiments. Preparatory literature review revealed a paucity of published information relative to …

Evaluation Of Metallurgical And Mechanical Properties Of Alsi10mg Produced By Selective Laser Melting, Luke J. Suttey

Graduate Theses & Non-Theses

Selective laser melting (SLM) additive manufacturing (AM) of metal powders has long been a focus in the study of AM due to the possibility of weight reduction, complex shape formation, and production cost savings. Although applicable to a variety of metals SLM AM of the AlSi10Mg alloy was studied in an attempt to characterize the effect of processing parameter and build angle variation on the final microstructural, fractographic, and mechanical properties of parts produced without any thermal post-processing techniques. Research was conducted on five build angles (0°, 30°, 45°, 60°, and 90°), and three Global Energy Densities (GED) (37.15, 45.39, …

Structural And Photoluminescence Properties Of Zno Thin Films Deposited By Ultrasonic Spray Pyrolysis, Iwan Sugihartono, Erfan Handoko, Vivi Fauzia, Artoto Arkundato, Lara Permata Sari

Makara Journal of Technology

Zinc oxide (ZnO) thin films on a silicon (Si) (111) substrate were grown herein using ultrasonic spray pyrolysis at 450 °C with different Zn concentrations. The ZnO thin films had X-ray diffraction patterns of a polycrystalline hexagonal wurtzite structure. The (002) and (101) peak intensities changed under different Zn concentrations. Furthermore, according to Scherer's and Stokes–Wilson equations, the crystallite size and the internal strain of the ZnO thin films in the (002) and (101) peaks changed with the Zn concentration. Optically, the photoluminescence spectra indicated that the ratio of the UV/GB emission of the ZnO thin films was the highest …

An Exploratory Study Of Sukuk Utilisation For Transportation Infrastructure Development In Indonesia, Fiona Lamari, Ayomi Dita Rarasati, Meilia Evita

Makara Journal of Technology

Investment in infrastructure is one of the principal drivers of the growth of the economy. For that reason, the Indonesian government has proposed an investment budget in the railway and sea and air transport sectors over the next 10 years. In order to overcome the burden of direct outflows and for the future, a study was conducted to lay down the framework of Shariah-compliant payments for the development of infrastructure in Indonesia in the transport sector. This paper aims to explore the opportunity and implementation of sukuk utilisation to develop transportation infrastructure. Secondary data study and interviews were selected for …

Small-Signal-Stability Enhancement Using A Power-System Stabilizer Based On The Cuckoo-Search Algorithm Against Contingency N-1 In The Sulselrabar 150-Kv System, Muhammad Ruswandi Djalal, Muhammad Yusuf Yunus, Herlambang Setiadi, Awan Uji Krismanto

Makara Journal of Technology

Small-signal stability is one of the main factors limiting power transmission in conventional power systems. This concern is primarily handled by adding damper windings of a synchronous generator and power-system stabilizer (PSS). However, due to the impact of the N-1 contingency, damper windings and a conventional PSS are insufficient to overcome this problem. Proper placement and design of the PSS are crucial for improving stability. One approach to optimizing the placement and tuning of the PSS is to use an artificial-intelligence method. Here, the cuckoo-search algorithm (CSA) is proposed to optimize the PSS tuning and placement. Based on simulation, it …

Isolation And Molecular Weight Characterization Of Tetragonula Laeviceps Honey Protein, Muhamad Sahlan, Nurul Azizah, Kazuaki Hakamada, Keiichi Noguchi, Masafumi Yohda

Makara Journal of Technology

The concentration of protein in honey is lower than polysaccharide. However, recently the honey’s protein is intensively studied and it showed that protein also have several biological activities such as antibacterial activity. The purpose of this research is to isolate and characterize Tetragonula laeviceps honey protein by determining the molecular weight. Honey protein of Trigona laeviceps was isolated using ultra-filtration with the membrane’s size of 30 kDa, then concentrated using tube membrane size 10 kDa. Molecular weight was analyzed by SDS PAGE. From the analysis, there was major protein band in honey produced by Tetragona laeviceps identified. The produced molecular …

Prerequisites For Public Acceptance Of Waste-To-Energy Plants: Evidence From Germany And Indonesia, Uwe Lahl, Barbara Zeschmar-Lahl

Makara Journal of Technology

Construction of waste incinerators often encounters resistance from the public. The minimum requirements for the ac- ceptance of these installations include modern air pollution control (APC) technology and safe disposal of residues. Confidence in the statements of government and government agencies as well as on those who support is an important point of acceptance. Independent scientific bodies such as universities can help to make this happen. In the case of the installation of waste into energy (WtE), such scientific support can be the measurement of emissions and their evalua- tion. Many products that enter the waste stream contain heavy metals, …

Hybrid Brain-Computer Interface: A Novel Method On The Integration Of Eeg And Semg Signal For Active Prosthetic Control, Reza Darmakusuma, Ary Setijadi Prihatmanto, Adi Indrayanto, Tati Latifah Mengko

Makara Journal of Technology

This paper describes a novel method for controlling active prosthetics by integrating surface electromyography (sEMG) and electroencephalograph signals to improve its intuitiveness. This paper also compares the new method (RTA-2) with other existing methods (AND and OR) for controlling active prosthetics. Based on analysis, RTA-2 features higher true positive rate (TPR) and balanced accuracy (BA) than AND method. On the other hand, the new method (RTA-2) yields lower false detection rate (FPR) than OR method. Analysis also shows that RTA-2 possesses equal TPR, FPR, and BA with the detection of movement intention using sEMG-based system. Although the RTA-2 method shows …

Seismic Response Analysis Along The Coastal Area Of Bengkulu During The September 2007 Earthquake, Lindung Zalbuin Mase

Makara Journal of Technology

A strong earthquake of 8.4 Mw occurred at the Sumatra Subduction Zone in September 12, 2007. The area that underwent the impact of the earthquake was located along the coastal area of the Bengkulu Province. A seismic ground response study was then performed with reference to the event. Several site investigations, including standard penetration test and shear wave velocity tests, were conducted to understand the subsoil condition. The data were used to analyze a ground response during the earthquake. The amplification factor of each site was obtained, and a comparison of the spectral accelerations was performed. The results showed that …

Coax-Fed Dipole-Type Applicator For Hepatic Cancer Rf Ablation, Basari Basari, Aditya Rakhmadi, Kazuyuki Saito

Makara Journal of Technology

Cancer is the third leading cause of mortality in the world and is one of the most difficult diseases to detect and cure. This fact motivates us to investigate a treatment method by using radiofrequency (RF) ablation. RF ablation therapy kills cancer cells by electromagnetically heating them up. The treatment uses an applicator that is inserted into the body to heat the cells. The cancer cells are exposed to a temperature of more than 60 °C in short duration (a few seconds to a few minutes), thereby causing cell destruction locally. To ensure effective treatment, a minimally invasive method is …

Nanostructural Origin Of Semiconductivity And Large Magnetoresistance In Epitaxial Nico2O4/Al2O3 Thin Films, Congmian Zhen, Xiaozhe Zhang, Wengang Wei, Wenzhe Guo, Ankit Pant, Xiaoshan Xu, Jian Shen, Li Ma, Denglu Hou

Xiaoshan Xu Papers

Despite low resistivity (~1 mΩ cm), metallic electrical transport has not been commonly observed in inverse spinel NiCo₂O₄, except in certain epitaxial thin films. Previous studies have stressed the effect of valence mixing and the degree of spinel inversion on the electrical conduction of NiCo₂O₄ films. In this work, we studied the effect of nanostructural disorder by comparing the NiCo₂O₄ epitaxial films grown on MgAl₂O₄ (1 1 1) and on Al₂O₃ (0 0 1) substrates. Although the optimal growth conditions are similar for the …

Atomic Probe Tomography And Creep Deformation Studies Of Highly Dynamic Metallic Systems: Copper-Zirconium Based Metallic Glass Alloys And Tin-Based Alloy, Chetarpa Yipyintum

Chulalongkorn University Theses and Dissertations (Chula ETD)

The early crystallization process of a Cu-Zr binary metallic glass was investigated by transmission electron microscopy (TEM) and atomic probe tomography (APT). The microstructural analysis was carried out using different characterization methods to see if the phase separation in different chemical compositions and chemical short-range orders were investigated by applying heat treatment under argon atmosphere in differential scanning calorimetry (DSC) chamber. Such a difference in the atomic arrangement of a given amorphous metallic structure is important, the actual characterization of such small difference is not practically easy. For the reason that there is an effect of the sample preparation method …

Corrosion Performance Of Zirconium-Based Passivations On Electroplated Zinc Nickel, Madison Morgan Reed

Masters Theses

“Performance requirements for Department of Defense (DoD) electrical components include corrosion and electrical contact resistance. Historically, electroplated cadmium with a chromate conversion coating (CrCC) has been used to meet corrosion and contact resistance standards. However, replacements are needed for these materials because they are toxic and carcinogenic. Electroplated γ-ZnNi has been identified as an acceptable alternative to Cd. This study evaluated commercially available Zr-based thin films and sealers as passivations for potential replacement of CrCCs. Ten different passivations were tested and compared with bare γ-ZnNi. X-Bond and Zircobond passivations were found to provide some improvement to the bare ZnNi corrosion …

Grain Refinement Of High Alloy Stainless Steels In Sand And Directionally Solidified Castings, Dustin Alan Arvola

Masters Theses

"The goal of this research project is to develop an industrially viable melting process that will control the crystallization macrostructure of austenitic grades of cast steels. Titanium nitride (TiN) has proven to be an effective grain refiner of austenite. Theoretical simulation and experimental application has led to the development of a repeatable grain refining melt process for austenitic stainless steel alloys.

Grain refinement of the as-cast structure of Cr-Ni stainless steel alloys solidified with primary FCC, BCC and dual FCC/BCC phases was studied experimentally. Refinement was achieved in both cast ferritic and austenitic grades. Dual solidification of …

Effect Of Microstructural Features On Steel Machinability, Mark C. Emmendorfer

Masters Theses

Non-metallic inclusions can have a tremendous impact on the machinability of steel. Some oxide inclusions such as alumina, spinel, and other refractory abrasive oxide inclusions can have a detrimental effect on machinability. Modification of oxide inclusions by calcium treatment can promote the formation of low melting point oxides such as anorthite and gehlenite inclusions that can assist in chip formation and form a lubricating layer on the rake surface of the machine tool. MnS is known to be beneficial to improving the machinability of steel. They assist in chip formation by being heavily deformed in the primary shear zone. Sulfide …

Effects And Limitations Of Residual Alloying Elements In Silicon Solid Solution Strengthened Ferritic Ductile Iron, Julia Scruton

Dissertations, Master's Theses and Master's Reports

Transitioning from traditional grades of ductile iron to solution strengthened ferritic ductile iron (SSFDI) grades can be difficult because of the need to reduce the amount of pearlite promoting elements, particularly copper and manganese, which are used in traditional grades. Knowing the acceptable threshold of residual alloying elements will allow for more cost-effective tailoring of the charge stream. Data were generated from a series of casting trials with the target grade of EN-GJS-500-14 where the levels of copper and manganese were varied from 0.05% to 0.3% and 0.15% to 0.4% respectively while maintaining silicon in the 3.8%-4.3% range. The pearlite …

Induced Ferromagnetism In Multilayered Graphene In Proximity With Cofe2o4, Himanshu Verma, Dereje Seifu, Shashi P. Karna, Haiping Hong, Mohindar S. Seehra

Faculty & Staff Scholarship

Composites of anisotropic diamagnetic multilayer Graphene (MLG) and ferrimagnetic CoFe2O4 (CFO) nanoparticles (NPs) were synthesized through a one-step sonication process in the presence of a surfactant. The samples were characterized at ambi- ent using x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy, magnetic force microscopy (MFM) and magnetometry (vibrating sample magnetometer). An induced ferromagnetism was observed in MLG with saturation magnetization MS = 18 emu/g(MLG). This induced ferromagnetism is attributed to ferrimagnetic CFO uniformly distributed on the surface of diamagnetic MLG. SEM images confirm uniform dense distribu- tion of CFO nanoparticles on MLG. MFM images …

Direct Strength Approach To Predict The Flexural Strength Of Cold-Formed Z-Section Purlins On Sloped Roofs, Ali Parva, Michael W. Seek

Engineering Technology Faculty Publications

In this study, the strength of cold-formed Z-section purlins is predicted considering the effects of roof slope in real roof systems. The study applies to simple span purlins with torsion restraints at support locations and at paired locations along the length of the member. A previously developed method has shown through comparisons to base tests that when the biaxial bending and torsion stresses are incorporated into the analysis, the Direct Strength Method can accurately predict the strength of a purlin. These stress distributions can deviate substantially from the constrained bending approximation typically assumed in analysis and therefore impacts the local …

Effect Of Thickness On The Structure And Corrosion Performance Of Sputtered Ce-Al-O Coatings On Al 2024-T3 Alloy Substrates, Yuanyuan Liu, Jiamu Huang, Lilu Qin, James B. Claypool, Matthew J. O'Keefe, Yiming Jiang

Materials Science and Engineering Faculty Research & Creative Works

Ce-Al-O coatings with thicknesses between ca. 136 nm and 1094 nm were deposited on Al 2024-T3 alloy substrates using magnetron co-sputtering of independent Al and CeO2 targets. The Ce-Al-O coatings with thicknesses from ca. 136 nm to 490 nm were compact, dense, and did not have distinct X-ray diffraction peaks. The ca. 1094 nm thick Ce-Al-O coating exhibited a columnar-textured outer layer ∼700 nm thick and a dense, ∼390 nm thick inner layer. X-ray photoelectron spectroscopy analysis revealed that the Ce-Al-O coatings contained Ce (III) species, and that the Al/Ce atomic ratio decreased with increasing coating thickness. Electrochemical corrosion data …

Interfacial Corrosion Of Copper And The Formation Of Copper Hydroxychloride, Mary Teague, Shengxi Li, Hongbo Cong

Williams Honors College, Honors Research Projects

Electrical circuitry is an industry, among many others, heavily using the element of copper. Ensuring the mechanical integrity of Cu is crucial, especially in salt environments, for the multifaceted composition of circuits. 4N NaCl solution (equilibrium concentration in ~84% RH) simulated this three-phase system. Rectangular Cu samples were partially immersed in both ambient and continuous lab air sparging atmospheres to understand waterline corrosion of the metal. Open circuit potentials (OCP) were continuously taken during the immersion testing for a maximum of 5 days. A scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS), Raman spectroscopy, and 3-D …

Design Of Shape-Conforming Nosecone For Optimal Fluid Flow From Transonic To Supersonic Range, Anna Tombazzi

Williams Honors College, Honors Research Projects

Modern flight vehicles, such as rockets, missiles, and airplanes, experience a force caused by forebody wave drag during the flight. This drag force is induced when the frontal point of each vehicle breaks the pressure wave during flight. Efforts to reduce this wave drag force to improve flight efficiency include modifying the nosecone profile of the flight vehicles to lower the drag force.

This project revolved around creating a design to make the transformation of nosecone shapes from a ¾ Parabolic profile to a ½ Power Series profile possible, mid-flight. Using a novel nosecone assembly, shape memory alloys (SMAs) and …

Development Of Oxide-Dispersion-Strengthened Nickel-Based Super Alloy Powders For Additive Manufacturing, Sizhe Huang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Oxide-Dispersion-Strengthened (ODS) Nickel-Based superalloy has been drawn a huge attention and developed with good oxidation resistance, corrosion resistance and high creep strength. It has been considered as critical materials for Additive Manufacturing (AM). The quality and the efficiency of fabrication methods of ODS limits the performance of itself on AM. The development of new type of ODS, new methodologies and evaluation techniques are required if the enhanced quality of ODS and enhanced efficiency of fabrication are to be achieved. Of the current fabrication techniques for AM, Gas Atomization (GA) is widely used since they can generate spherical powders with high …