William Stratton Ph.D. Thesis - MINDS@UW Home

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4.5: Summary ……………………………………………………………….…… 90 Chapter 5: Al88Y7Fe5 and Al88Y7Fe4Cu1 ………………………………………………… 91 5.1: Microalloying Al88Y7Fe5 with Cu ………………………………………….. 93 5.2: Experiment Addendum …………………………………………………….. 96 5.3: Al88Y7Fe4Cu1 Results ………………………………………………………. 98 5.4: Al88Y7Fe4Cu1 Discussion …………………………………………………… 103 5.5: Summary ……………………………………………………………………. 107 Chapter 6: Conclusions ………………………………………………………………….. 108 6.1: Future work …………………………………………………………………. 110 References ………………………………………………………………………………… 112 vi
List of Figures Figure Page Figure 1.1: Schematic plots of physical changes associated with Tg. Tg depends on the cooling rate of the solid, with a faster cooling rate leading to a higher Tg than a slower cooling rate. The continuous change of the (a) specific volume (first derivative of the Gibbs free energy) and the discontinuous change of the (b) specific heat (second derivative of the Gibbs free energy) show that Tg is a second order phase transformation. Between the melting temperature Tm and Tg the amorphous material is a supercooled liquid, meaning it is below the melting point of the material but can still flow. Figure 1.2: Isothermal calorimetry traces for a nucleation (a) versus growth control glass (b). Since energy is first needed to form then grow nuclei in a nucleation controlled material, the isothermal signal first increases and decreases. Since nuclei already exist in a growth controlled material, the isothermal signal only decreases. Figure 1.3: Representative TTT, DSC and isothermal calorimetry for nucleation control versus growth control. Nucleation control amorphous alloys will show a distinct Tg in DSC, while growth control amorphous alloys do not. Figure 1.4: V(k) with representative images, higher V with more speckled images means more MRO compared to images with less speckle. Figure 1.5: Schematic difference between STEM FEM and TEM FEM. STEM FEM with a STEM translates the probe to acquire multiple nanodiffraction patterns while TEM FEM with a TEM tilts the beam to obtain a real space image. TEM FEM with usually covers multiple more sample area in the V calculation compared to STEM FEM. Figure 1.6: V(k) for Al88Y7Fe5 by TEM and STEM FEM. TEM FEM was at 1.6 nm spatial resolution; STEM FEM was at 2.8 nm spatial resolution. While the peak position is conserved between the techniques, STEM FEM has values of V that are ten times those of TEM FEM. TEM data was acquired at the University of 2 5 6 16 18 20 vii
Page 1 and 2: MEDIUM RANGE ORDER IN HIGH ALUMINUM
Page 3 and 4: To my wife Elisabeth i
Page 5 and 6: Abstract High Al-content metallic a
Page 7: Table of Contents List of Figures
Page 11 and 12: Figure 2.8: V(Φ) at varying values
Page 13 and 14: electron beam exposure. The sharp f
Page 15 and 16: Figure 5.7: FEM data for Al88Y7Fe5
Page 17 and 18: Chapter 1. Introduction Amorphous m
Page 19 and 20: Material Type Tg ( o C) Reference P
Page 21 and 22: dH / dt (arb. units) time Figure 1.
Page 23 and 24: enough to avoid any nucleation onse
Page 25 and 26: nanocrystals are thermally stable u
Page 27 and 28: The structural difference between t
Page 29 and 30: Structures for various metallic gla
Page 31 and 32: ( , ) V k Q = ( r, , ) − ( r, , )
Page 33 and 34: of 1-3 nm is readily achievable in
Page 35 and 36: than the STEM FEM V 66,67,84 . This
Page 37 and 38: interesting behavior upon devitrifi
Page 39 and 40: Λ is a characteristic ordering len
Page 41 and 42: amorphous matrix crystal l R d R bi
Page 43 and 44: For a crystal oriented to a Bragg c
Page 45 and 46: number of crystals in a column will
Page 47 and 48: 3 d π 2 Rt max Zmax Φ = . (2.21)
Page 49 and 50: eciprocal lattice point 1 d hkl awa
Page 51 and 52: A hkl 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0
Page 53 and 54: V(C hklΦ,d) 0.4 0.3 0.2 0.1 0.4 0.
Page 55 and 56: V(C 111 Φ) 0.12 0.10 0.08 0.06 0.0
Page 57 and 58: Φ = 6π d ( 72 − 6π + π ρ) m
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V(t) 0.16 0.14 0.12 0.10 0.08 0.06
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⎛ 3 ⎛ 4 6tΩ⎞⎞ d = ⎜ Chkl
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Chapter 3. Experimental Set-up Prep
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A B 0.25 1/Å 0.25 1/Å Figure 3.1:
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〈IBF〉, to the bright field inte
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Once the relative thickness is know
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Given that FEM is a quantitative el
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eam at a uniform intensity across t
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Low Filtering Limit ω l (Å -1 ) 0
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sample 101 . Much of the influence
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3.07 Thickness Dependant Thinning A
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Residual XRD Intensity (arb. units)
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Intensity (arb. units) 0.30 Al 88 Y
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3.08 Beam Induced Crystallization o
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Fraction of Atoms 0 120 keV 100 200
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V(k) x10 -3 10 8 6 4 2 Al 92 Sm 8 P
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to produce an accurate FEM data set
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Deformation Al 92Sm 8 sample: Rapid
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intensity (arb. units) 3 4 {111} {2
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Al2O3 Al hkl d (1/nm) hkl d (1/nm)
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easons. First, the as-spun V(k) for
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atoms locally organized into an FCC
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in Figure 4.6. Still, this begs the
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Φ 0.20 0.15 0.10 0.05 0.00 10 21 A
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Chapter 5. Al88Y7Fe5 and Al88Y7Fe4C
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diffracting condition through the m
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increases the number of Al nanocrys
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Fraction of nanocrystals x10 -3 Fra
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Al 88 Y 7 Fe 5 Enthalpy (J/g) 0 -1
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Al 88Y 7Fe 5 100 nm Al 88Y 7Fe 4Cu
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5.04 Al88Y7Fe4Cu1 Discussion The de
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FEM is sensitive to both critical a
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devitrified structure has the possi
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fraction between the as quenched ma
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number, etc.) can give insight to t
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24. Liquid Metals Website, http://w
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66. Voyles, P. M., Gibson, J. M. &
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105. Zuo, J. M. Electron detection
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