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Materials Science and Engineering Commons

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Metallurgy

Doctoral Dissertations

Theses/Dissertations

2018

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Full-Text Articles in Materials Science and Engineering

Chemistry, Design, And Processing Of Two-Stage Trip Steel, Daniel M. Field Jan 2018

Chemistry, Design, And Processing Of Two-Stage Trip Steel, Daniel M. Field

Doctoral Dissertations

"A regular solution model was developed to calculate the chemical driving force for α-martensite formation, ΔGλ→ αChem. A model for the strain energy, ΔGλ→αstr, was formulated utilizing the Young’s modulus (E), lattice misfit squared (δ²), and molar volume (Ω) which opposed the chemical driving force for α-martensite formation. The MαS was determined at a temperature at which ΔGλ→αChem + ΔGλ→αstr = 0. In conjunction with a previously developed ε-martensite model, a means of predicting the volume fraction of λ-austenite was determined; and it was shown that for values …


Micro-Slotting Technique For Measurement Of Local Residual Stress In Metallic Materials, Elizabeth Anne Burns Jan 2018

Micro-Slotting Technique For Measurement Of Local Residual Stress In Metallic Materials, Elizabeth Anne Burns

Doctoral Dissertations

"Micro-slotting, a micro-scale relaxation residual stress measurement technique, has been shown in recent years to be a reliable method for measuring local residual stresses in metallic materials. This technique employs an SEM-focused ion beam system for milling and imaging, digital image correlation software to track displacements due to residual stress relaxation, and finite element analysis for interpolation of the original local stress state. In this research, a micro-slotting procedure was established using finite element models and was used to obtain sub-surface residual stress measurements on machined and shot peened planar Ti-6Al-4V samples. These measurements were compared to macro-scale XRD residual …