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Nanomechanical Characterization And Comparison Of Additively Manufactured Grcop-42 Alloy, Trupti Suresh Mali
Nanomechanical Characterization And Comparison Of Additively Manufactured Grcop-42 Alloy, Trupti Suresh Mali
Electronic Theses and Dissertations
In an aggressive thermomechanical environment, the superior mechanical as well as thermal properties of materials play an essential role. GRCop which is a copper-based alloy developed by NASA has the potential to fulfill the requirements necessary for hightemperature applications such as the combustion chamber of liquid rocket engines. The first alloy of this family, GRCop-84 (Cu-8 wt.% Cr-4 wt.% Nb) was discovered followed with the development of GRCop-42 (Cu-4 wt.% Cr, 2 wt.% Nb). The reduction in alloying element percentage enhanced thermal conductivity with less built time while maintaining the strength of the material. The conventional fabrication is replaced with …
Reclamation Of Fused Silica From Investment Shells Used For Casting Steel, Samuel L. Holt
Reclamation Of Fused Silica From Investment Shells Used For Casting Steel, Samuel L. Holt
Electronic Theses and Dissertations
Fused silica is widely used for investment casting shell molds. Fused silica shells are discarded after being used for casting one time. This is due to the transformation of fused silica to beta cristobalite above 1652℉ (900℃). To reduce cost and waste of investment casting foundries, this study is exploring a method to inhibit transformation of fused silica and reclaim it from high temperature investment casting shells. This research has employed firing to minimalize fused silica transformation to cristobalite. The phase transformation is minimalized due to sintering and coarsening of the particles during firing. Coarsening reduces surface area to volume …
Control Of Pore Characteristics Of Porous Silicon Using Non-Toxic Electrochemical Etching For Photovoltaics And Supercapacitor Applications, Utpal Saha
Electronic Theses and Dissertations
Porous silicon has exhibited lower reflectance and higher surface area than the pristine silicon. This property of porous silicon can be applied to photovoltaic (PV) application for more efficient silicon solar cells and for higher performance of supercapacitors. NH4Fl electrolytic etching solution has been used to fabricate porous silicon, but the control of pore morphology of silicon is achieved only by controlling the time. Therefore, it is urgently required to use other etching parameters such as voltage and current to achieve flexible control of pore properties. Porous silicon can also be used to fabricate supercapacitors. An established approach to make …