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Articles 541 - 570 of 585
Full-Text Articles in Materials Science and Engineering
The Current State Of Research On Academic Dishonesty Among Engineering Students, Trevor S. Harding, Donald D. Carpenter, Susan M. Montgomery, Nicholas H. Steneck
The Current State Of Research On Academic Dishonesty Among Engineering Students, Trevor S. Harding, Donald D. Carpenter, Susan M. Montgomery, Nicholas H. Steneck
Materials Engineering
Academic dishonesty, or cheating, has become a serious problem at colleges and universities. This is particularly true of engineering students who, are among the most likely to cheat in college. The present paper reviews the literature as a basis of broadly understanding academic dishonesty. This discussion focuses on three primary issues: (1) perceptions of and attitudes towards cheating, (2) reasons for student cheating, and (3) methods of promoting academic integrity. A current research project being developed by the authors is also discussed. The premise of this research is that students are constantly making ethical judgements between the pressure to cheat …
Hfco2 Laves Phas Intermetallics - Part I: Solubility Limits And Defect Mechanisms, Katherine C. Chen, Eric J. Peterson, Dan J. Thoma
Hfco2 Laves Phas Intermetallics - Part I: Solubility Limits And Defect Mechanisms, Katherine C. Chen, Eric J. Peterson, Dan J. Thoma
Materials Engineering
Solubility limits and constitutional defects in Laves phase intermetallics are investigated with the C15 HfCo2 system. Several binary alloy compositions based on HfCo2 are characterized by optical and scanning electron microscopy (SEM), electron microprobe analysis (EPMA), X-ray diffraction (XRD), and density measurements. Rietveld refinements of XRD scans are used to determine lattice constants, anisotropic strain parameters, and atomic occupancies. Compositional trends are compared against predicted or calculated trends due to an anti-site substitution or vacancy defect mechanism. Geometric models and atomic size factors are used to establish solubility limits and to give insight into defect mechanisms. Results from …
Hfco2 Laves Phase Intermetallics - Part Ii: Elastic And Mechanical Properties As A Function Of Composition, Katherine C. Chen, Fuming Chu, Paul G. Kotula, Dan Thoma
Hfco2 Laves Phase Intermetallics - Part Ii: Elastic And Mechanical Properties As A Function Of Composition, Katherine C. Chen, Fuming Chu, Paul G. Kotula, Dan Thoma
Materials Engineering
In efforts to establish and understand structure–property relationships in Laves phase intermetallics, elastic and mechanical properties are studied as a function of composition in the C15 HfCo2 system. Elastic constants and Debye temperatures are determined by resonant ultrasound spectroscopy (RUS) at room temperature. A maximum near the stoichiometric Laves composition is revealed with the Young's modulus, bulk modulus, and Poisson's ratio. In addition, a slight drop in shear modulus is found with Co-rich compositions, and the Debye temperature increases with Co-content. Room temperature Vickers indentation is performed to assess the microhardness and fracture toughness of the HfCo2 alloys. …
Asee Student Chapters: From Student Members To Faculty, Jennifer Kadlowec, Kurt Degoede, Trevor S. Harding, Christian Lorenz
Asee Student Chapters: From Student Members To Faculty, Jennifer Kadlowec, Kurt Degoede, Trevor S. Harding, Christian Lorenz
Materials Engineering
The University of Michigan Student Chapter of the American Society for Engineering Education has grown from a small core group of founding members, who organized panel discussions for the graduate student community, into a flourishing student organization, which continues to grow in membership and events. The purpose of this paper is to promote graduate student chapters of the ASEE and demonstrate the positive impact that student member participation has had, particularly for those who have recently entered academia. Many events and activities of the University of Michigan Student Chapter of the American Society for Engineering Education (UM-ASEE Student Chapter) will …
The Foundation Series On Corrosion: Integrating Science, Math, Engineering & Technology In A Lab Setting, Linda Vanasupa, Heather Smith, Blair London, Katherine C. Chen, David Niebuhr, Lanny Griffin, Jeff Jones
The Foundation Series On Corrosion: Integrating Science, Math, Engineering & Technology In A Lab Setting, Linda Vanasupa, Heather Smith, Blair London, Katherine C. Chen, David Niebuhr, Lanny Griffin, Jeff Jones
Materials Engineering
We have developed a laboratory module focusing on the subject of corrosion. The module itself is designed to be completed in one three-hour session. It consists of three parts: I. The Impact of Corrosion Media, II. The Impact of Corroding Materials, III. The Impact of Anode/Cathode Sizes. Our objectives in developing this module were to address the need for clear bridges between math, science and technology in the engineering curriculum and to provide a means of faculty development primarily at community colleges. As a result, it was designed to allow the engineering student to experience the synergy of science, math …
Useful Approaches To Preventing Academic Dishonesty In The Classroom, Trevor S. Harding
Useful Approaches To Preventing Academic Dishonesty In The Classroom, Trevor S. Harding
Materials Engineering
Over the past three decades, academic dishonesty (a.k.a. cheating) has become an increasingly common occurrence among college-aged students, and engineering students are known to be among the most frequent culprits. At most universities, cheating is dealt with after the fact. Few institutions go beyond drafting an academic integrity policy to prevent cheating before it happens. The same situation exists in the classroom. The majority of college professors report doing little or nothing to reduce the frequency of cheating in their classes, usually because of a lack of awareness of its occurrence. And when cheating is observed, faculty overwhelmingly choose to …
On The Frequency And Causes Of Academic Dishonesty Among Engineering Students, Trevor S. Harding
On The Frequency And Causes Of Academic Dishonesty Among Engineering Students, Trevor S. Harding
Materials Engineering
According to studies of self-reported academic dishonesty conducted over time, cheating among college students has been on the increase since at least the 1940’s. This is especially true for engineering students who are now among the most likely to cheat compared to other disciplines. This paper will present a synopsis of the literature on academic dishonesty. In addition, the results of a pilot study on cheating among engineering students conducted at a small mid-western private engineering school are described. Engineering students in an introductory engineering materials course were asked to complete a survey on their perceptions of cheating; therefore, all …
Plasma Deposition Of Spin Chucks To Reduce Contamination Of Silicon Wafers, Richard N. Savage, Emir Gurer, Ed C. Lee
Plasma Deposition Of Spin Chucks To Reduce Contamination Of Silicon Wafers, Richard N. Savage, Emir Gurer, Ed C. Lee
Materials Engineering
An apparatus for delivering a fluidic media to a wafer includes a housing defining a process chamber. A fluidic media delivery member is coupled to the process chamber. A rotatable chuck is positioned in the process chamber. The rotatable chuck has a wafer support surface coated with a coating material. A vacuum supply line is coupled to the rotatable chuck.
Heat Treatment Of Gamma Titanium Aluminide Alloys, Thomas J. Kelly, Michael J. Weimer, Curtiss M. Austin, Blair London, Donald E. Larson Jr., Dean A. Wheeler
Heat Treatment Of Gamma Titanium Aluminide Alloys, Thomas J. Kelly, Michael J. Weimer, Curtiss M. Austin, Blair London, Donald E. Larson Jr., Dean A. Wheeler
Materials Engineering
A gamma titanium aluminide alloy article, is prepared using a piece of a gamma titanium aluminide alloy having a composition capable of forming alpha, alpha-2, and gamma phases. The alpha transus temperature of the gamma titanium aluminide alloy piece is determined. The gamma titanium aluminide alloy piece is consolidated by hot isostatic pressing at a temperature of from about 50 F. to about 250 F. below the alpha transus temperature and at a pressure of from about 10,000 to about 30,000 pounds per square inch, for a duration of from about 1 to about 20 hours. The piece is heat …
Method And Apparatus For Adaptive Process Control Of Critical Dimensions During Spin Coating Process, Richard N. Savage, Emir Gurer
Method And Apparatus For Adaptive Process Control Of Critical Dimensions During Spin Coating Process, Richard N. Savage, Emir Gurer
Materials Engineering
A spin coating process for controlling the mean thickness of photoresist on the surface of a semiconductor wafer. The wafer surface has a central axis normal to the surface. The process comprises the steps of applying the solution to the wafer surface and spinning the wafer about the central axis at a spindle speed until the solution has dried. The spindle speed is a function of the desired mean thickness of the photoresist, the barometric pressure and the relative humidity. The spindle speed is determined from a statistical model described by the equation: MT=A+BxRH+CxBP+D/SS1/2 wherein: MT is mean thickness …
Cheating: Student Attitudes And Practical Approachs To Dealing With It, Trevor S. Harding
Cheating: Student Attitudes And Practical Approachs To Dealing With It, Trevor S. Harding
Materials Engineering
The preliminary results of educational research conducted at Kettering University is described in which students in an introductory engineering materials course (MFGE-370) were asked to complete a survey on their perceptions of cheating. The overall objective of the research was to determine those things students believed constituted cheating, the frequency to which they cheat and their attitudes about what steps could be taken to curtail cheating within a course. Practical approaches to effectively dealing with cheating are also discussed including using learning objectives for writing fair tests, promoting group work through cooperative learning teams, holding review sessions before tests and …
Effect Of Foreign Object Damage On The Fatigue Strength Of An Xd™ Γ-Tial Alloy, Trevor S. Harding, J. Wayne Jones
Effect Of Foreign Object Damage On The Fatigue Strength Of An Xd™ Γ-Tial Alloy, Trevor S. Harding, J. Wayne Jones
Materials Engineering
High cycle fatigue has become the leading cause of failure in gas turbine engine blades in recent years [1]. The majority of these failures were associated with surface damage such as foreign object damage (FOD). Therefore, the ability of a material to resist impact damage and the subsequent fatigue propagation of any cracks that may result has become a crucial design consideration. Substantial research has been conducted on the effects of simulated FOD in conventional turbine blade materials where the formation of cracks at the impact site was not a common occurrence [2, 3 and 4]. However, impacts of more …
The Effect Of Impact Damage On The Room-Temperature Fatigue Behavior Of Γ-Tial, Trevor S. Harding, J. Wayne Jones
The Effect Of Impact Damage On The Room-Temperature Fatigue Behavior Of Γ-Tial, Trevor S. Harding, J. Wayne Jones
Materials Engineering
The relationship between impact damage and the fatigue behavior of γ-TiAl has been examined. Axial fatigue specimens fabricated from cast Ti-47.9Al-2.0Cr-1.9Nb (to be referred to as 48-2-2) and Ti-47.3Al-2.2Nb-0.5Mn-0.4W-0.4Mo-0.23Si (to be referred to as WMS) alloys were damaged by impact under controlled conditions with a 60 deg wedge-shaped indenter to simulate assembly-related damage in low-pressure turbine blades. The level of damage produced was quantified and found to correlate well with the peak load of the impact event. The WMS alloy exhibited a greater resistance to impact damage due to its higher yield strength and lamellar microstructure. A measure of the …
Implementing An Engineering Teaching Development Program For Graduate Student Instructors, Sara Soderstrom, Christian Lorenz, Michael Keinath, Trevor S. Harding
Implementing An Engineering Teaching Development Program For Graduate Student Instructors, Sara Soderstrom, Christian Lorenz, Michael Keinath, Trevor S. Harding
Materials Engineering
The Engineering Teaching Development Project (ETDP), a pilot program started by the student chapter of ASEE at the University of Michigan, is a multi-component program designed to improve the long-term teaching skills of graduate student instructors (GSIs) in the College of Engineering. The first component of the ETDP is college-wide pedagogical workshop series. These workshops are conducted by nationally recognized engineering educators invited by the ASEE student chapter. The topics of these workshops include cooperative learning, diversity in the classroom, and classroom assessment techniques. These workshops offer a means of continual improvement for all of the educators in the university, …
Photoresist Coating Process Control With Solvent Vapor Sensor, Richard N. Savage, Herbert Litvak, Emir Gurer
Photoresist Coating Process Control With Solvent Vapor Sensor, Richard N. Savage, Herbert Litvak, Emir Gurer
Materials Engineering
An apparatus for spin coating surfaces with liquid polymer comprises a spin coating chamber having a rotatable chuck for supporting an object to be coated. A distributor introduces gases into the chamber. A solvent vapor and carrier gas supply provides a carrier gas having a controlled level of solvent vapor therein within the range of from 0 to saturation concentrations of solvent vapor. A solvent vapor sensor is positioned with respect to the coating chamber to produce signals which correspond to the concentration of solvent vapor in the coating chamber. A control means is connected to the solvent vapor concentration …
Behavior Of Gamma Tial Subjected To Impact Damage And Elevated Temperature Fatigue, Trevor S. Harding, J. Wayne Jones
Behavior Of Gamma Tial Subjected To Impact Damage And Elevated Temperature Fatigue, Trevor S. Harding, J. Wayne Jones
Materials Engineering
Gamma titanium aluminide has received significant attention in recent years as a candidate material for use in aerospace and industrial gas turbine engine applications. In particular, these materials offer significant weight reductions (densities are less than half that of nickel-based superalloys), high specific strength retention at elevated temperature and high specific stiffness which is particularly important in vibrating components such as blades. This combination of weight savings and good mechanical properties has led to the possibility that γ-TiAl may be a suitable replacement for nickel-based alloys, such as Inconel 718, in low pressure turbine blades without significant redesign of the …
Theoretical And Experimental Investigation On The Low Temperature Properties Of The Nbcr2 Laves Phase, Dan J. Thoma, Chu Fuming, Katherine C. Chen, Paul G. Kotula, Terence E. Mitchell, John M. Wills, Alim Ormeci, Shao Ping Chen, Robert C. Albers
Theoretical And Experimental Investigation On The Low Temperature Properties Of The Nbcr2 Laves Phase, Dan J. Thoma, Chu Fuming, Katherine C. Chen, Paul G. Kotula, Terence E. Mitchell, John M. Wills, Alim Ormeci, Shao Ping Chen, Robert C. Albers
Materials Engineering
This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The goal of the project was to develop methodologies in which to define and improve the properties of NbCr2 so that the high temperature structural applications of alloys based upon this would not be limited by the low-temperature brittle behavior of the intermetallic. We accomplished this task by (1) understanding the defect structure and deformation mechanisms in Laves phases, (2) electronic and geometric contributions to phase stability and alloying behavior, and (3) novel processing of dual phase (Laves/bcc) …
Training Graduate Student Instructors Effectively: The University Of Michigan Model, Trevor S. Harding
Training Graduate Student Instructors Effectively: The University Of Michigan Model, Trevor S. Harding
Materials Engineering
No abstract provided.
Room Temperature Fatique Response Of Γ-Tial To Impact Damage, Trevor S. Harding, J. Wayne Jones, P. S. Steif, T. M. Pollock
Room Temperature Fatique Response Of Γ-Tial To Impact Damage, Trevor S. Harding, J. Wayne Jones, P. S. Steif, T. M. Pollock
Materials Engineering
Gamma based titanium aluminides have received considerable attention recently as candidate materials in gas turbine applications, particularly low pressure turbine blades (1–3). Their low density and high specific stiffness, result in potentially significant weight savings in structures such as gas turbine engines if substituted for current materials. Two γ-TiAl microstructures are predominately identified in the literature: a lamellar microstructure consisting of alternating plates of γ and α2, and a duplex microstructure consisting of equiaxed γ grains and lamellar colonies (3,4). Lamellar alloys generally exhibit better fracture toughness and fatigue crack growth resistance (5–7). Duplex alloys, on the other …
Microstructures And Mechanical Properties Of Two-Phase Alloys Based On Nbcr2, Katherine C. Chen, Paul G . Kotula, Carl M. Cady, Michael E. Mauro, Dan J. Thoma
Microstructures And Mechanical Properties Of Two-Phase Alloys Based On Nbcr2, Katherine C. Chen, Paul G . Kotula, Carl M. Cady, Michael E. Mauro, Dan J. Thoma
Materials Engineering
A two-phase, NbCrTi alloy (bcc + C15 Laves phase) has been developed using several alloy design methodologies. In efforts to understand processing-microstructure-property relationships, different processing routes were employed. The resulting microstructures and mechanical properties are discussed and compared. Plasma arc melted (PAM) samples served to establish baseline, as-cast properties. In addition, a novel processing technique, involving decomposition of a supersaturated and metastable precursor phase during hot isostatic pressing (HIP), was used to produce a refined, equilibrium two-phase microstructure. Quasi-static compression tests as a function of temperature were performed on both alloy types. Different deformation mechanisms were encountered based upon temperature …
Defects And Site Occupancies In Nb-Cr-Ti C15 Laves Phase Alloys, P. G. Kotula, C. B. Carter, Katherine C. Chen, Dan J. Thoma, F. Chu, T. E. Mitchell
Defects And Site Occupancies In Nb-Cr-Ti C15 Laves Phase Alloys, P. G. Kotula, C. B. Carter, Katherine C. Chen, Dan J. Thoma, F. Chu, T. E. Mitchell
Materials Engineering
No abstract provided.
Promoting Excellence In Education With An Outstanding Student Instructor Award Program, Jennifer Kadlowec, Justin Shriver, Trevor S. Harding, Charles Choi
Promoting Excellence In Education With An Outstanding Student Instructor Award Program, Jennifer Kadlowec, Justin Shriver, Trevor S. Harding, Charles Choi
Materials Engineering
The ASEE Student Chapter at the University of Michigan in conjunction with the College of Engineering has developed and organized an annual Outstanding Student Instructor Award in recognition of excellence in engineering education. The award not only acknowledges the outstanding contributions of the individuals selected for the award, but also coincides with the ASEE’s goals of promoting excellence in engineering education and attracting new members. The paper outlines the planning procedures developed since the inception of the award in 1994 and provides suggestions and insights for other ASEE Student Chapters to create and organize such an award.
The Effects Of Beryllium Additions On The Oxidation Of Nickel Aluminide And Titanium Aluminide Based Intermetallics, R. H. Hanrahan Jr., Katherine C. Chen, M. P. Brady
The Effects Of Beryllium Additions On The Oxidation Of Nickel Aluminide And Titanium Aluminide Based Intermetallics, R. H. Hanrahan Jr., Katherine C. Chen, M. P. Brady
Materials Engineering
The effects of Be additions on the oxidation behavior of β-NiAl in moist air at 1000°C and borderline alumina-forming y (TiAI) + Laves Ti-Al-Cr based alloys at 800°C and 1000°C in dry and moist air were investigated. The addition of Be to β-NiAl suppressed the formation of transient alumina, and resulted in the formation of a protective BeAl2O4 spinel phase. In dry air, the addition of Be to the Ti-AI-Cr alloys also resulted in the formation of a protective BeAl2O4 spinel phase. In moist air, only Ti-AlCr- Be alloys with a high Cr content …
Factors Affecting The Room-Temperature Mechanical Properties Of Ticr2-Base Laves Phase Alloys, Katherine C. Chen, Samuel M. Allen, James D. Livingston
Factors Affecting The Room-Temperature Mechanical Properties Of Ticr2-Base Laves Phase Alloys, Katherine C. Chen, Samuel M. Allen, James D. Livingston
Materials Engineering
Various effects on the room-temperature mechanical properties of TiCr2-base alloys have been assessed in efforts to improve the toughness of Laves phase intermetallics (AB2). Systematic studies were performed on: (i) single-phase stoichiometric and nonstoichiometric TiCr2, (ii) TiCr2-base ternary Laves phases, and (iii) two-phase binary alloys containing TiCr2. In order to make quantitative comparisons among the different alloys, Vickers indentation was used to obtain hardness and fracture toughness values. Within the single-phase field, constitutional defects accounted for the compositional dependencies of properties, and may aid the synchroshear deformation process. Ternary Laves …
Formation Of A Metastable Bcc Solid Solution And Decomposition To A C15 Laves Phase In Melt-Spun Crnb10Ti10, Katherine C. Chen, P. G. Kotula, F. Chu, Dan J. Thoma
Formation Of A Metastable Bcc Solid Solution And Decomposition To A C15 Laves Phase In Melt-Spun Crnb10Ti10, Katherine C. Chen, P. G. Kotula, F. Chu, Dan J. Thoma
Materials Engineering
A metastable, disordered bcc phase has been formed from the melt in a Cr-rich alloy of the Nb-Cr-Ti system, where large volume fractions of the Laves phase would develop under equilibrium solidification conditions. X-ray diffraction (XRD) studies and lattice constant determinations confirm that the melt-spun ribbons contain a bcc phase beyond its terminal solid solution limits. Solidification pathways are proposed based upon metastable and equilibrium phase diagrams. Microstructures have been studied using optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Cross-sectional TEM reveals tiny, dispersed Laves phase precipitates within the metastable bcc grains near the chill (wheel) …
Orientation Relationships In The System Nb-Nbcr2, P. G. Kotula, Katherine C. Chen, Dan J. Thoma, F. Chu, T. E. Mitchell
Orientation Relationships In The System Nb-Nbcr2, P. G. Kotula, Katherine C. Chen, Dan J. Thoma, F. Chu, T. E. Mitchell
Materials Engineering
No abstract provided.
Assessment Of The Compositional Influences On The Toughness Of Ticr2-Base Laves Phase Alloys, Katherine C. Chen, Samuel M. Allen, James D. Livingston
Assessment Of The Compositional Influences On The Toughness Of Ticr2-Base Laves Phase Alloys, Katherine C. Chen, Samuel M. Allen, James D. Livingston
Materials Engineering
Systematic studies of alloys based on TiCr, have been performed in order to improve the toughness of Laves phase intermetallics. The extent to which alloy compositions and annealing treatments influence the toughness was quantified by Vickers indentation. The single-phase Laves behavior was first established by studying stoichiometric and nonstoichiometric TiCr,. Next, alloying effects were investigated with ternary Laves phases based on TiCr2. Different microstructures of two-phase alloys consisting of (Ti,Cr)-bcc+TiCr2, were also examined. Various toughening theories based on vacancies, site-substitutions, crystal structure (C14, C36, or Cl5) stabilization, and the presence of a …
Evidence Of Heterogeneous Substructure Development During Primary Creep Of Ti-6al-2sn-4zr-2mo, R. W. Hayes, Cecil Rhodes, Blair London
Evidence Of Heterogeneous Substructure Development During Primary Creep Of Ti-6al-2sn-4zr-2mo, R. W. Hayes, Cecil Rhodes, Blair London
Materials Engineering
No Abstract.
Morphology, Deformation, And Defect Structures Of Ticr2 In Ti-Cr Alloys, Katherine C. Chen, Samuel M. Allen, James D. Livingston
Morphology, Deformation, And Defect Structures Of Ticr2 In Ti-Cr Alloys, Katherine C. Chen, Samuel M. Allen, James D. Livingston
Materials Engineering
The morphologies and defect structures of TiCr2 in several Ti-Cr alloys have been examined by optical metallography, x-ray diffraction, and transmission electron microscopy (TEM), in order to explore the room-temperature deformability of the Laves phase TiCr2. The morphology of the Laves phase was found to be dependent upon alloy composition and annealing temperature. Samples deformed by compression have also been studied using TEM. Comparisons of microstructures before and after deformation suggest an increase in twin, stacking faul4 and dislocation density within the Laves phase, indicating some but not extensive room-temperature deformability.
On The Creep Deformation Of A Cast Near Gamma Tial Alloy Ti-48al-1nb, R. W. Hayes, B. London
On The Creep Deformation Of A Cast Near Gamma Tial Alloy Ti-48al-1nb, R. W. Hayes, B. London
Materials Engineering
The steady-state creep deformation behavior of a cast two phase gamma TiAl alloy having the composition Ti---48Al---1Nb (at.%) has been studied. Tension creep tests using the stress increment technique (θθ2θ3) were conducted over the temperature range of 704–850°C at constant initial applied stress level of 103.4–241.3 MPa. The activation energy for creep over the temperature and stress regime of this study varied 317.5 kJ/mol (137.8 MPa) up to 341.0 kJ/mol (206.8 MPa) with an average value of 326.4 kJ/mol. This is well within the range of values previously measured for gamma TiAl alloys where creep controlled by volume diffusion has …