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Full-Text Articles in Engineering
Creep Resistance And Microstructure In Binary Aluminum Cerium Alloy Produced By Laser Powder Bed Fusion, Jillian Ann Stinehart
Creep Resistance And Microstructure In Binary Aluminum Cerium Alloy Produced By Laser Powder Bed Fusion, Jillian Ann Stinehart
Master's Theses (2009 -)
Currently, the only commercially available aluminum alloy for additive manufacturing (AM) is AlSi10Mg, which is not suitable for high temperature applications. Al-Ce based alloys have been shown to be highly printable, cost-efficient alloys. Compared to cast Al-Ce alloys, the eutectic features are refined (<1μm), which give AM Al-10Ce favorable strength and ductility at room temperature. The low diffusivity and solubility of cerium in aluminum improve the retention of mechanical properties at high temperatures. In order to quantify the effect of cerium on the thermal stability of AM aluminum and show its suitability for high-temperature applications, Al-10Ce was creep tested between 60-77% of its absolute melting temperature. The creep performance of AM Al-10Ce was favorable compared to that of cast binary Al-Ce and AM AlSi10Mg and was comparable to that of cast ternary Al-Ce alloys. The stress exponent, n, was approximately 1 in the low stress regime and 5-7 in the high stress regime. The activation energy was 231kJ/mol. In comparison, both cast binary Al-Ce and AM AlSi10Mg have higher stress exponents and lower activation energies, showing AM Al-10Ce to be more creep resistant. After creep testing, slight grain coarsening was observed, while grain orientation remained unchanged. The melt pool boundaries (MPBs) faded in appearance after creep testing, and the number of columnar grains decreased.
Investigation Of Aluminum Equation Of State Generation, Aaron Ward
Investigation Of Aluminum Equation Of State Generation, Aaron Ward
Master's Theses (2009 -)
There are many forms and methods to construct equations of state, EOSs. These methods are usually tailored for the particular problem of interest. Here, the EOSs of interest are those used in modeling shock responses. These EOSs cover a wide range of physical characteristics such as detonation and explosions, armor and anti-armor materials, and space structures protection. Aluminum will be the primary focus of this work. Aluminum was chosen because it has been studied in great length in the shock regime and is a common component in shock experiments and space type vehicles.
Mesoscale Behavior Of An Aluminum-Manganese Dioxide-Epoxy Mixture Under Shock Loading: From Milli To Nano-Sized Aluminum Particles, Andrew Fraser
Mesoscale Behavior Of An Aluminum-Manganese Dioxide-Epoxy Mixture Under Shock Loading: From Milli To Nano-Sized Aluminum Particles, Andrew Fraser
Master's Theses (2009 -)
The main focus of this thesis is to explore the dynamic shock compaction of multiple component mixtures, specifically Al-MnO2-Epoxy. This will be facilitated by initially simulating the bulk dynamic response in a mesoscale configuration and then comparing these results to experimental data. The mesoscale simulations were performed in the shock code CTH. The first section will discuss the matching of experimental data to computational results. With the goal of determining the bulk shock Hugoniot, a one-dimensional flyer plate configuration was created while using a grain-geometry imported from an scanning electron microscope (SEM) micrograph of the mixture. Both the …