Open Access. Powered by Scholars. Published by Universities.®
- Publication
- Publication Type
Articles 1 - 6 of 6
Full-Text Articles in Engineering
Printing, Characterization, And Mechanical Testing Of Additively Manufactured Refractory Metal Alloys, Brianna M. Sexton
Printing, Characterization, And Mechanical Testing Of Additively Manufactured Refractory Metal Alloys, Brianna M. Sexton
Browse all Theses and Dissertations
Refractory metal alloys in the tungsten molybdenum rhenium ternary system were additively manufactured using laser power bed fusion. Four ternary alloys with varying concentrations of tungsten, molybdenum, and rhenium were manufactured and manufactured again with an addition of 1 wt% hafnium carbide. Samples were heat treated to heal cracks, reduce porosity, and reduce inhomogeneity. Material microstructure was characterized before and after heat treatment using microscopy, energy dispersive x-ray spectroscopy, and electron backscatter diffraction mapping. Mechanical testing was conducted on both three-point bend specimens and compression specimens, resulting in maximum bending strengths of 677.86 MPa, and maximum compression 0.2% yield strengths …
An Adapted Approach To Process Mapping Across Alloy Systems And Additive Manufacturing Processes, Luke Charles Sheridan
An Adapted Approach To Process Mapping Across Alloy Systems And Additive Manufacturing Processes, Luke Charles Sheridan
Browse all Theses and Dissertations
The continually growing market for metal components fabricated using additive manufacturing (AM) processes has called for a greater understanding of the effects of process variables on the melt pool geometry and microstructure in manufactured components for various alloy systems. Process Mapping is a general approach that traces the influence of process parameters to thermal behavior and feature development during AM processing. Previous work has focused mainly on Ti-6Al-4V (Ti64), but this work uses novel mathematical derivations and adapted process mapping methodologies to construct new geometric, thermal, and microstructural process maps for Ti64 and two nickel superalloy material systems. This work …
Elucidating The Role Of Microstructure, Texture, And Microtexture On The Dwell Fatigue Response Of Ti-6al-4v, Alec Mitchell Blankenship
Elucidating The Role Of Microstructure, Texture, And Microtexture On The Dwell Fatigue Response Of Ti-6al-4v, Alec Mitchell Blankenship
Browse all Theses and Dissertations
Ambient temperature dwell sensitivity is known to be deleterious to the fatigue response of near-alpha titanium alloys. Dwell fatigue refers to the presence of a sustained hold at peak stress as opposed to the continuous variation of normal cyclic fatigue loading. This reduction in failure life-times from dwell loading is attributed to early crack nucleation and faster crack propagation. The degradation is the result of plastic anisotropy on the microstructural scale along with tendency of titanium alloys to creep at low temperatures at stresses well below the 0.2% offset yield strength. Despite being the most widely used titanium alloy, Ti-6Al-4V …
Effect Of Free-Edges On Melt Pool Geometry And Solidification Microstructure In Beam-Based Fabrication Methods, Joy Elizabeth Davis
Effect Of Free-Edges On Melt Pool Geometry And Solidification Microstructure In Beam-Based Fabrication Methods, Joy Elizabeth Davis
Browse all Theses and Dissertations
Laser and electron beam-based additive manufacturing of Ti-6Al-4V are under consideration for application to aerospace components. A critical concern for these processes is the ability to obtain a consistent and desirable microstructure and corresponding mechanical properties of the deposit. Based on the Rosenthal solution for a moving point-heat source, recent work has developed simulation-based process maps for the thermal conditions controlling microstructure (grain size and morphology) in beam-based deposition of semi-infinite geometries, where a steady-state melt pool exists away from free-edges. In the current study, the Rosenthal solution is modified to include the effects of free-edges. This is accomplished by …
Effect Of Finite Geometry On Solidification Microstructure In Beam-Based Fabrication Of Thin Wall Structures, Satish C. Kuchi
Effect Of Finite Geometry On Solidification Microstructure In Beam-Based Fabrication Of Thin Wall Structures, Satish C. Kuchi
Browse all Theses and Dissertations
With the advent of Rapid Protyping (RP) in the manufacturing industry, many newtechnologies came into development for quick fabrication of materials. One of the most versatile fabrication process among them is additive manufacturing. Laser based manufacturing (LBM) and electron beam manufacturing (EBM) processes use the energy from a laser or electron beam to build up structures layer by layer directly from powdered metals and wire feed stock. It has been determined from previous work that solidification cooling rate and thermal gradients are the important factors for controlling microstructure (grain size and morphology) and resulting mechanical properties of the deposit. The …
Titanium Alloyed With Boron, Seshacharyulu Tamirisakandala, Daniel B. Miracle, Raghavan Srinivasan, Jay S. Gunasekera
Titanium Alloyed With Boron, Seshacharyulu Tamirisakandala, Daniel B. Miracle, Raghavan Srinivasan, Jay S. Gunasekera
Mechanical and Materials Engineering Faculty Publications
Small additions of boron to conventional titanium alloys have been found to produce significant changes to the microstructures and associated properties. Grain refinement and improved strength and stiffness are first-order effects, which lead to possibilities for developing novel and affordable processing methodologies and to enhance performance over conventional titanium alloys. In this article, we introduce this new class of titanium alloys and describe unique formability benefits achieved via engineering microstructures.