Structure Property Process Relations Of Solid State Additively Manufactured Aerospace Aluminum Alloys
Download Structure Property Process Relations Of Solid State Additively Manufactured Aerospace Aluminum Alloys full books in PDF, epub, and Kindle. Read online free Structure Property Process Relations Of Solid State Additively Manufactured Aerospace Aluminum Alloys ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
| Author | : Craig Joseph Taylor Mason |
| Publisher | : |
| Total Pages | : 314 |
| Release | : 2020 |
| Genre | : |
| ISBN | : |
Additive manufacturing processes provide new avenues to additively repair or manufacture complex aerospace components. There has been limited success in additively manufacturing aluminum alloys and aluminum metal matrix composites that are susceptible to hot-cracking. Recently, the development of a transformative solid-state additive manufacturing process, Additive Friction Stir-Deposition (AFS-D), incorporated the benefits of additive manufacturing and severe plastic deformation processes that provided a new path to fabricate fully-dense aluminum alloy and aluminum metal matrix composite structures. In this work, the microstructural evolution and mechanical response of an Al-Cu-Mg metal matrix composite (MMC) containing 20 weight percent Al2O3 and an AA7050 isogrid structure was additively manufactured through the AFS-D process. Microstructural characterization of the tempered and overaged Al-MMC employed optical microscopy, Scanning Electron Microscopy, and Electron Backscatter Diffraction. Additionally, to quantify the mechanical response of the tempered and overaged Al-MMC, quasi-static tensile experiments were conducted in the longitudinal and transverse orientation. Dynamic tensile testing was performed on the tempered and overaged AFS-D Al-Cu-Mg material in the transverse orientation using a Split-Hopkinson pressure bar. The resulting microstructural and mechanical analysis was captured via the internal state variable (ISV) plasticity damage model. The model is consistent with continuum level kinematics, kinetics, and thermodynamics. The following research provides a foundation for rapidly additively manufacture large MMC structures through AFS-D. This study produced a fully dense AA7050 isogrid structure was manufactured without the need for additional alloying elements. Three sections of the component that exhibit differing thermomechanical processing history were evaluated for the resulting microstructure and mechanical response. The microstructural characterization of the as-deposited AA7050 employed TEM, SEM, and EBSD. The as-deposited AA7050 exhibited a refinement of the constituent particles and grains within the microstructure. Additionally, to quantify the mechanical response of the as-deposited AA7050, quasi-static tensile and high rate tensile experiments were conducted. The Internal-State Variable Plasticity model was successfully modified to be able to capture material anisotropy as a function of precipitate free zones and secondary phases size within the grain.
| Author | : Sadie Cole Beck |
| Publisher | : |
| Total Pages | : |
| Release | : 2021 |
| Genre | : Electronic dissertations |
| ISBN | : |
Additive manufacturing provides alternatives to traditional manufacturing methods. Equipment footprint, energy use, maintenance considerations, component geometries and material selection are all being reconsidered on the rise of additive manufacturing. Aluminum alloys are of particular interest in the additive manufacturing realm because of their strength-to-weight ratio, general availability, and performance in austere environments. However, it s critical that the strengthening mechanisms that make aluminum alloys so desirable are preserved post additive processing. Additive Friction Stir Deposition (AFSD) is a novel additive manufacturing process that utilizes solid-state plastic deformation to create near-net shaped, layered depositions. Because the process is still being developed, the microstructural and mechanical performance of deposited aluminum alloys have not been fully characterized. In this work, the process-structure-property-performance of a precipitate-hardened (AA6061-T6) and strain-hardened (AA5083-H131) aluminum alloy as processed through AFSD, were quantified. A standard post deposition heat treatment (PDHT) was applied to AA6061 AFSD material, an Al-Mg-Si alloy. The as-deposited material exhibited a refined grain structure, reduced tensile strength from the heat treated feedstock, and increased elongation to failure. The PDHT AFSD material exhibited tensile properties characteristic of a T6 temper through the regrowth of strengthening precipitates. The other material of interest, Al-Mg-Mn alloy (AA5083-H131), a strain-hardened alloy, was processed through AFSD using two methods of machine feeding: recycled chip and solid rod. The thermo-mechanical processing of AFSD resulted in an exchange of strengthening mechanisms removing the wrought material of strength from strain-hardening and replacing it with grain boundary strengthening. The monotonic tensile results demonstrated a reduced yield strength and comparable elastic modulus and ultimate tensile strength to the AA5083-H131 wrought control. The fatigue results demonstrated comparable fatigue performance, primarily between the recycled chip feedstock and wrought AA5083-H131. A strength model and a multistage fatigue model were employed to capture the tensile and fatigue performance for AFSD AA5083. Dynamic compression testing was performed using a Split-Hopkinson pressure bar to quantify strain rate dependence. Experiments reveal that the flow stress of AA5083-H131 and AA5083 AFSD are dependent on the strain rate under compression loading. Furthermore, resulting mechanical performance was captured by the internal state variable (ISV) plasticity-damage model.
| Author | : Oscar Gabriel Rivera Almeyda |
| Publisher | : |
| Total Pages | : 97 |
| Release | : 2017 |
| Genre | : Electronic dissertations |
| ISBN | : |
| Author | : Benjamin Andrew Rutherford |
| Publisher | : |
| Total Pages | : 252 |
| Release | : 2020 |
| Genre | : |
| ISBN | : |
Additive manufacturing processes have become a leading technology for research innovation. Additive manufacturing offers the capacity to fabricate complex, near net shape components and the possibility to repair existing components. The vast majority of additive processes are fusion-based, relying on melting and solidification, which can lead to poor mechanical performance due to intense thermal gradients leading to solidification cracking and columnar dendritic grain growth. Additive Friction Stir-Deposition (AFS-D) is a novel technique that implements solid-state severe deformation to create depositions additively. As such, the AFS-D process offers potential to fabricate fully dense components with wrought-like mechanical performance and microstructure. Likewise, AFS-D avoids the intense thermal gradients of fusion welding that leads to solidification cracking in lightweight materials in aerospace applications, such as aluminum alloys. In this research, the process-structure-property relationship is quantified by means of microstructure characterization and mechanical evaluation of AFS-D AA6061. To understand the process-structure-property relationships of AFS-D as-deposited AA6061, test specimens in two orthogonal directions, longitudinal and build, were subjected to quasi-static monotonic tension and strain-controlled fatigue testing. Microstructural evaluation revealed the refinement of constituent particles in AFS-D AA6061, in addition to dynamic recrystallization and grain refinement. Mechanical results indicated homogeneous strength between the two directions investigated at a similar strength to wrought AA6061-O, and fatigue performance similar to the wrought in the longitudinal direction. Microstructural examination of a standard heat treatment for the T6 temper of AA6061 on AFS-D AA6061 was conducted. This led to mechanical performance superior in strength to the control wrought AA6061-T651 in monotonic tension tests, and similar fatigue performance to the as-deposited AFS-D AA6061 and wrought AA6061. Fractography revealed an evolution in the deformation behavior for post deposition heat treated AFS-D AA6061 compared to the as-deposited specimens. Lastly, the mean strain effects of heat treated AFS-D AA6061 and a lightweight rolled aerospace aluminum alloy, AA2099-T83, are quantified and captured in this work. The tensile stable cycle mean stress proved detrimental to the fatigue performance of aluminum alloys. A modified strain-based Morrow model is proposed in this work that successfully captures the effect of tensile mean strain loading conditions on these aluminum alloys.
| Author | : Dustin Zane Avery |
| Publisher | : |
| Total Pages | : |
| Release | : 2020 |
| Genre | : Electronic dissertations |
| ISBN | : |
Additive manufacturing has emerged as the leading forefront alternative technology for fabricating and repairing complex geometry aerospace components. However, a majority of the additive processes are fusion-based, which can create underachieving mechanical responses from materials that are susceptible to hot cracking and phase transformations. A solid-state severe deformation-based additive manufacturing process, Additive Friction Stir-Deposition (AFS-D), offers an innovative solution and a new path to fabricate or repair components to achieve fully-dense depositions with wrought-like mechanical performance. In this work, the process-structure-property relationships will be quantified, through extensive characterization of the microstructural evolution and mechanical response of IN625, a fabricated free-standing deposition of AA7075, and lastly, repaired AA7075 plate additively repaired through the AFS-D process. To quantify the fatigue behavior of the as-deposited IN625, stress-life experiments were conducted, where improved fatigue resistance was observed compared to the feedstock. Post-mortem analysis of the as-deposited IN625 revealed a similar fatigue nucleation and growth mechanism to the feedstock for most of the specimens. Lastly, a microstructure-sensitive fatigue life model was utilized to elucidate structure-property fatigue damage mechanisms. The microstructural characterization of the as-deposited AA7075 employed optical, scanning electron microscope, and electron backscatter diffraction. The as-deposited AA7075 exhibited a refinement of the constituent particles and grains within the microstructure. Additionally, to quantify the fatigue behavior of the as-deposited AA7075, strain-life experiments were conducted, where a reduction in fatigue resistance was observed compared to the heat-treated feedstock. Post-mortem analysis of the as-deposited AA7075 revealed a change in the fatigue nucleation and growth mechanisms compared to the control feedstock. Lastly, a microstructure-sensitive fatigue life model was employed to capture the fatigue life for the first time in AFS-D aluminum alloys. In this work, we quantify the fatigue performance of repaired AA7075. Simulated crack repair was carried out by machining a rounded groove into a plate, which was then additively repaired using the AFS-D process. An extensive microstructural characterization of as-deposited and heat-treated conditions was conducted to elucidate the microstructural evolution of the repaired plate. Additionally, the mechanical performance of the heat-treated repair was then quantified, as well as the fatigue performance, and fatigue crack initiation mechanisms.
| Author | : Hang Z. Yu |
| Publisher | : Elsevier |
| Total Pages | : 351 |
| Release | : 2022-07-19 |
| Genre | : Technology & Engineering |
| ISBN | : 0128243953 |
Additive Friction Stir Deposition is a comprehensive summary of the state-of-the-art understanding on this emerging solid-state additive manufacturing technology. Sections cover additive friction stir deposition, encompassing advances in processing science, metallurgical science and innovative applications. The book presents a clear description of underlying physical phenomena, shows how the process determines the printing quality, covers resultant microstructure and properties in the as-printed state, highlights its key capabilities and limitations, and explores niche applications in repair, cladding and multi-material 3D printing. Serving as an educational and research guide, this book aims to provide a holistic picture of additive friction stir deposition-based solid-state additive manufacturing as well as a thorough comparison to conventional beam-based metal additive manufacturing, such as powder bed fusion and directed energy deposition. Provides a clear process description of additive friction stir deposition and highlights key capabilities Summarizes the current research and application of additive friction stir deposition, including material flow, microstructure evolution, repair and dissimilar material cladding Discusses future applications and areas of research for this technology
| Author | : Lillianne P. Troeger |
| Publisher | : |
| Total Pages | : 64 |
| Release | : 2000 |
| Genre | : Alloys |
| ISBN | : |
Advanced manufacturing processes such as near-net-shape forming can reduce production costs and increase the reliability of launch vehicle and airframe structural components through the reduction of material scrap and part count and the minimization of joints. The current research is an investigation of the processing-microstruture-property relationships for shear formed cylinders of the Al-Cu-Li-Mg-Ag alloy 2195 for space applications and the Al-Cu-Mg-Ag alloy C415 for airframe applications. Cylinders which had undergone various amounts of shear-forming strain were studied to correlate the grain structure, texture, and mechanical properties developed during and after shear forming.
| Author | : Rajiv Mishra |
| Publisher | : Springer |
| Total Pages | : 356 |
| Release | : 2016-12-01 |
| Genre | : Technology & Engineering |
| ISBN | : 3319481088 |
This collection focuses on all aspects of science and technology related to friction stir welding and processing.
| Author | : Brandon James Phillips |
| Publisher | : |
| Total Pages | : 262 |
| Release | : 2021 |
| Genre | : |
| ISBN | : |
Additive manufacturing is a rapidly growing industry with numerous technologies to suit a variety of applications. However, each application has its own inherent flaws and niches. Aluminum alloys are difficult for the more popular fusion-based additive manufacturing techniques due to the intense thermal gradients generating distortion and selective vaporization of alloying elements. To subjugate some of the issues, the solid-state Additive Friction Stir-Deposition (AFS-D) method was proposed to produce high quality, defect free aluminum deposits. This work investigates the process-structure-property relationships of two popular commercial aluminum alloys employed extensively by consumer, transportation, and defense industries. The first work on process-deformation characteristics of AA6061 were evaluated by producing microhardness profiles taken from the cross-section of builds to produce relationships between mechanical characteristics and machine parameters. Resulting average hardness values were plotted against the processing window and used to determine comparative samples for microstructural analysis. Electron backscatter diffraction and transmission electron microscopy was conducted to characterize the microstructural evolution of depositions. This study provides a succinct, multiscale characterization of as-deposited AFS-D AA6061 to expound the effect of the high-shear solid-state AM process. The subsequent investigation on AA6061 is the first investigation of the process-structure-property relationships of AFS-D in an overlapping, parallel raster deposit. In particular, the deposit produced in this work explores the influence of severe plastic deformation on the as-deposited microstructure and tensile response of material that overlaps in parallel layers at the outer edge of the tool. This study sought to determine the viability of producing large scale structural components larger than the track-width of the AFS-D tool. The final study quantifies the microstructural evolution and consequential tensile response of AA5083. A brief examination of the effect of AFS-D processing parameters was undertaken to determine preferential processing conditions for a larger, free-standing AA5083 structure. Optical and scanning electron microscopy evaluate the microstructural evolution of particles and grain morphology. Tensile properties were evaluated in the longitudinal and vertical build directions, and subsequent fractography discovered the influence of lubrication on the variable mechanical response.
| Author | : George Stubblefield |
| Publisher | : |
| Total Pages | : |
| Release | : 2021 |
| Genre | : Electronic dissertations |
| ISBN | : |
Additive friction stir-deposition (AFS-D) is a nascent additive manufacturing process shown to have better mechanical properties of deposited material than conventional techniques. While significant experimental research has been conducted on AFS-D, relatively little computational research exists for AFS-D. Simulating AFS-D is challenging because traditional finite element approaches fail to accommodate severe deformation. One solution is to use a meshfree framework, such as smoothed particle hydrodynamics (SPH), which better handles large deformation processes. This work aims to create a meshfree framework, improve it, and utilize it to better understand AFS-D and provide predictive power to improve AFS-D processing.Firstly, a meshfree framework was laid out to describe the underlying mechanics and SPH equations. Several AFS-depositions were created while monitoring substrate temperature for use in model calibration. The meshfree framework showed good agreement with the substrate temperature and build profile results. Previously unforeseen phenomena, such as the temperature dip under the stir zone, were revealed in the simulations. Simulations also revealed the relationship between actuator feed rate and processing temperature and plastic strain. To inform future AFS-D research and developments with the meshfree framework, a study was undertaken to compare constitutive models for AFS-D simulations. Two different AA6061 tempers were considered for this study: T6 and O. The constitutive models were calibrated against experimental torsion data at a variety of strain rates and temperatures. Constitutive model selection was found to have a major impact on simulation peak values, temperature, stress, strain, and build profiles. Finally, the meshfree framework was then applied for particle tracking analysis. Two types of depositions were created: one using an anodized feedstock to track oxide distribution in the deposition, which is analogous to material flow from the outside of the feedstock, and one using a copper wire core feedstock to track copper distribution in the deposition, which is analogous to material flow from the inside of the feedstock. Results revealed the tendency of oxides to flow to the retreating side. The copper wire was mainly deposited in a clear line on the advancing side, with some fragments scattered through the deposition. Unique insight into material flow behavior was illustrated with the meshfree framework.
