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Full-Text Articles in Engineering
Premartensitic Elasticity Of Fe-Ni Invars, Bryce Linn Shriver
Premartensitic Elasticity Of Fe-Ni Invars, Bryce Linn Shriver
Doctoral Dissertations
"The premartensitic temperature dependence of ultrasonic wave propagation in Fe-30 pct Ni polycrystals and Fe-32 pct Ni single crystals was measured by using a continuous wave technique. As the temperature was lowered to within 10°C of the Ms, a nonlinear decrease of the relative shear velocity was observed. This effect is related to dislocation stacking fault instabilities which may trigger the martensitic phase transformation. In addition, the single crystals show a frequency dependence of the shear elastic constant C' well above the Ms. The dispersion is believed to be caused by fluctuations in the anisotropic molecular …
Initial Surface Reactions And Nucleation Kinetics Of Boron On Atomically Clean Molybdenum Substrates, Richard Eugene Moore
Initial Surface Reactions And Nucleation Kinetics Of Boron On Atomically Clean Molybdenum Substrates, Richard Eugene Moore
Doctoral Dissertations
"A study of the chemical vapor deposition (CVD) of boron from boron triiodide (BI3) on molybdenum has been done with field emission microscopy (FEM) and low energy electron diffraction (LEED).
A correlation of the efficiency by which BI3 is effectively dissociated to form adsorbed boron, and the temperature of the substrate has been shown through work function measurements on the boron covered molybdenum field emitter surfaces. The boron-induced work function change of molybdenum has been shown to be in agreement with a theoretical model which predicts positive, as well as negative work functions for adsorbate-substrate systems. It …
Prebainitic Phenomena In Aisi 86b80 And 0.8c-5.3ni Steels, Chung Lim
Prebainitic Phenomena In Aisi 86b80 And 0.8c-5.3ni Steels, Chung Lim
Doctoral Dissertations
"An ultrasonic investigation shows that the prebainitic kinetics of AISI 86B80 and 0.8C-5.3Ni steels follow t2/3 and or t1 time laws in the lower bainite temperature region. The data analysis indicates that these kinetics signal carbon segregation to dislocations. The simple time laws are interrupted at the bainite start time. It is shown that at this time the carbon depleted regions around dislocations transform martensitically. The lower bainite reaction is thus initiated by the formation of supersaturated ferrite through carbon segregation and the subsequent local martensitic transformation"--Abstract, page iii.