J. Wayne Jones - US grants

The objective of this research program is to investigate the influence of ion beam modification on the cyclic deformation behavior and resulting near-surface damage accumulation processes which lead to fatigue crack initiation in Ni-Al alloys. Materials ranging from pure nickel single crystals to the Ni3Al nickel-aluminum intermetallic compound are being ion implanted (for alloying or ion beam mixing) and the materials are being characterized using Rutherford backscattering, ion channeling, and transmission electron microscopy. Mechanical property studies will include analyses of surface residual stresses and hardness, surface damage accumulation as a function of plastic strain, and fatigue crack initiation.

9411141 Was The objective of this work is to explore the use of ion beam assisted deposition (IBAD) to control the microstructure and interface properties of microlaminates. The results should provide a more fundamental understanding of factors controlling strength and toughness in these systems. Niobium/alumina is selected as the model, high temperature system to explore IBAD's effect on grain size, morphology, texture and ensuing strength of the ductile layer. It may be possible to control the metal-oxide interface strength by controlling the orientation relationship and the impurity composition at the interface. Although the depositions are done at high temperature (600 degrees C) and still higher temperature annealing is conducted to assess microstructural stability, the focus of the mechanical properties study is the toughness of the microlaminate at ambient temperature. %%% The scientific approach is based on the idea that ion beam assisted deposition provides improved control over the structure of individual lamellae and interfaces in microlaminates, thereby improving the toughness and strength of these materials for high temperature applications as structural and coating materials. ***

This ultra-low load indentation instrument will provide excellent capability for highly spatially resolved, ultralow load indentation on a wide variety of materials, and will enable a significant enhancement and extension of existing NSF-sponsored research aimed at understanding and improving the mechanical and physical properties of advanced materials and materials systems. There is immediate need for this capability in a large number of university research activities that span a wide spectrum of materials that are synthesized by a variety of advanced techniques. The commonality of these activities, with respect to the proposed instrumentation acquisition, is that the materials under study either involve extremely small microstructural scale or are synthesized in small quantities or with small bulk dimensions (e.g. thin films, microlaminates and coatings) that severely limit the use of conventional experimental methods for the study of synthesis/structure/property relationships. Examples include, ductile phase toughening in metal/oxide microlaminates produced by ion beam deposition, film softening effects in intermetallics and refractory metals and the role of low energy ion beam assisted deposition on the synthesis and properties of carbon nitride. Other studies involve examination of the relationships between mechanical behavior and cooperative molecular relaxations in polymers to fundamental studies of mechanical properties and microstructure in ordered polymers and an investigation of the influence of damage accumulation processes during fatigue of ceramic matrix composites.

Institution: University of Michigan
Proposal Number: EIA 0090006
PI: Sandra Gregerman
Title: Information Technology Pathways in Academe: Identifying Barriers for Women and Minority Students

This CISE Information Technology Workforce (ITW) proposal requests funds to study the factors that contribute to the small numbers of women and underrepresented minorities who obtain degrees in computer science (CS) and computer engineering (CE) at a major research university. Both quantitative and qualitative protocols will be used to determine why diverse students do not elect to follow academic career paths in CS and CE fields. Specifically, the project will consist of five parts: the Academic/Career Pathways Study, the Student Perceptions and Perspective Study, the Student Beliefs and Attitudes Study, the Course-taking Pattern and Retention Study, and the Faculty Perceptions and Attitudes Study. The first four studies will also look at the influence of program interventions such as the Undergraduate Research Opportunity Program and the Women in Science and Engineering Residence Program. This project has the potential to provide valuable insights into the recruitment and retention of women and underrepresented minorities in IT majors.

This project investigates the long life fatigue behavior of cast aluminum and magnesium structural alloys that find application in automotive and other technologies where lightweight materials are required. An objective of the study is to develop accurate models of crack initiation and short crack growth that can be used for predicting fatigue life. Very long lifetimes will be achieved in a practical timeframe using ultrasonic fatigue in which cyclic loading is applied at frequencies of approximately 20 kHz. The proposed method is far more cost effective than the conventional techniques that are extremely time consuming. The proposed program will examine the fundamental mechanisms responsible for the presence or absence of endurance limits in this important set of alloys. A significant effort will be focused on the potential use of ultrasonic fatigue techniques as a viable alternative or replacement for more conventional testing methods, especially where critical fatigue lives are in the very long life regime. This proposed GOALI program would continue a successful collaboration between the University of Michigan and the Ford Research Laboratories (FRL) of Ford Motor Company. The co-PI will co-advise a PhD student on this project. The educational impact of this work lies in close contact of the graduate students with the industrial counterpart through summer internships as well as the research direction by the co-investigator from Ford.

This project provides an opportunity to graduate research students and university personnel to work with industrial counterparts at the Ford Motor Company in developing cast aluminum and magnesium alloys with very long fatigue life. The results of the study will benefit not only automotive industry but also technologies that require lightweight fatigue resistant metallic alloys. The research will establish new techniques of characterizing very long fatigue lifetimes that find many practical applications by taking advantage of the expertise and facilities at the academia and industry.

The grant investigates fundamental aspects of solidification, phase equilibria and deformation mechanisms in order to establish a foundation for the design of future high temperature magnesium systems. Phase equilibria and microsegregation will be studied in two quaternary systems, Mg-Al-Ca-Sr and Mg-Al-Ca-Ce, followed by high temperature deformation using conventional microscopy along with high-resolution strain mapping techniques. The casting experiments will be made at casting facilities at Ford Motor Company and Eck Industries Inc. Computational thermodynamics and phase equilibria will be used to optimize the alloy compositions. A major goal is to structure an efficient combination of experiments and computation to accelerate alloy design in complex structural alloy systems. The research is a collaborative program between the University of Michigan, University of Wisconsin and the Ford Motor Company.

The grant allows an effort to develop new high temperature structural magnesium alloys for transportation industry applications, where vehicle weight reduction is a critical element of achieving greater performance and fuel efficiency. An important goal of the proposed research will be to develop in the United States a more concentrated research effort on high temperature cast magnesium alloys and to provide a nucleus of research activity that will train students and postdoctoral fellows in the fundamentals of magnesium alloy design. Beyond this, the program will also develop an educational module on Mg for mechanical engineers and high school teachers participating in a summer camp for high school science teachers hosted by the University of Michigan and sponsored by ASM International, SAE and the Minerals Metals and Materials Society.

TECHNICAL: Magnesium alloys have the lowest density among all structural alloys and possess high specific strength, but new alloys must be developed for use in the service temperature range of 150-250 C. The identification of new alloying approaches that provide strengthening and stability at these temperatures, within the constraints of casting processes that are viable for automotive-scale production, remains a critical materials challenge. The relative lack of fundamental understanding of the behavior of potential high temperature magnesium alloys systems, compared to that for other structural alloy systems, has been identified as a critical obstacle to significant progress in the search for new lightweight, high temperature magnesium systems. To address this a collaborative research program (FRG) between the University of Michigan and the University of Wisconsin, with strong collaboration from Ford Motor Company and General Motors is initiated. Key gaps in the fundamental understanding of solidification, phase equilibria and deformation mechanisms in selected magnesium alloy systems will be investigated in order to establish a strong foundation for the design of alloys that meet the multiple demands required for potential use at high temperature. This will be accomplished by: (1) selection of promising systems on which future alloy development programs are likely to be conducted, (2) establishment of full thermodynamic descriptions of these systems through a combined modeling and experimental effort, (3) evaluation of key aspects of the solidification behavior of these systems under realistic casting conditions and (4) investigation of mechanisms of high temperature deformation creep. Two quaternary systems, Mg-Al-Ca-Sr and Mg-Al-Ca-Nd, will initially motivate the research and will permit us to build on existing academic and industrial collaborations. Anticipated outcomes include (1) definition of microstructural modification strategies for improvement of creep properties, (2) identification of higher order elemental additions that can be used to alter solidification paths for critical microstructural control, (3) realistic approaches for improving the stability of intermetallic phases near the grain boundaries, (4) refined thermodynamic descriptions and alloy design tools and (5) new quantitative approaches for evaluation of solidification and casting behavior of Mg-based systems. NON-TECHNICAL: The research program is designed to stimulate a more concentrated national research effort on high temperature cast magnesium alloys, by serving as a nucleus of research activity and university/industry collaboration. The educational experience of the undergraduate and graduate students in the program will be greatly enhanced by interactions with industrial personnel as well as by direct access to their unique research facilities, particularly those of the Ford Motor Company and General Motors. A particular strength of the core collaborative group is the physical proximity of the University of Michigan and the University of Wisconsin to each other and to the U.S. automotive manufacturers (and suppliers). The program would bring the U.S. academic activity on lightweight Mg alloys closer (but certainly not equivalent) to observed levels of research effort in Asia and Europe. The program will also enhance academic courses within the core MSE curricula at both Michigan and Wisconsin. Finally, resources from this program relating to energy efficiency and lightweight materials will be made available to the ASM International High School Teachers Camp, which is hosted annually at the University of Michigan.