Shock deformation twinning in molybdenum and a comparison of deformation twinning in shock-loaded BCC and FCC metals

1978 ◽  
Vol 36 (1) ◽  
pp. 590-591
Author(s):  
L.E. Murr ◽  
K. Wongwiwat
Keyword(s):  
Pulse Duration ◽  
Shock Loading ◽  
Impedance Matching ◽  
Deformation Twinning ◽  
Loading Test ◽  
Fcc Metals ◽  
Grain Sizes ◽  
Shock Deformation ◽  
Deformation Twins ◽  
Matching Techniques

Verbraak reported deformation twins to have been formed in shock-loaded molybdenum from observations by optical metallography. Attempts to verify the existence of deformation twins in shock-loaded molybdenum by Murr, et al. were unsuccessful at pressures ranging up to 21 GPa (210 kbars) at a constant pulse duration of 2 μs. Since the conditions under which Verbraak originally observed deformation twins were not well documented, a study was undertaken to reinvestigate the shock deformation of molybdenum in a range of pressures and pulse durations.Molybdenum sheets (0.0025 cm thick and 0.025 cm thick) were annealed to produce several grain sizes and shock loaded in molybdenum sandwiches and assemblies (spall plates and momentum traps) by impacting them with stainless steel flyer plates as outlined previously. Pressure experiments were performed at 140, 260, and 350 kbars (corrected pressure values using impedance matching techniques) at a constant pulse duration of 2 μs while two additional experiments were conducted at 260 kbars by shock loading test assemblies at pulse durations of 0.5 μs and 8 μs.

scholarly journals Unique transition of yielding mechanism and unexpected activation of deformation twinning in ultrafine grained Fe-31Mn-3Al-3Si alloy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yu Bai ◽  
Hiroki Kitamura ◽  
Si Gao ◽  
Yanzhong Tian ◽  
Nokeun Park ◽  
...  
Keyword(s):  
Grain Refinement ◽  
Twip Steel ◽  
Deformation Twinning ◽  
Ultrafine Grain ◽  
Yield Drop ◽  
Grain Sizes ◽  
Deformation Twins ◽  
Ultrafine Grained ◽  
The Mean

AbstractTensile mechanical properties of fully recrystallized TWIP steel specimens having various grain sizes (d) ranging from 0.79 μm to 85.6 μm were investigated. It was confirmed that the UFG specimens having the mean grain sizes of 1.5 μm or smaller abnormally showed discontinuous yielding characterized by a clear yield-drop while the specimens having grain sizes larger than 2.4 μm showed normal continuous yielding. In-situ synchrotron radiation XRD showed dislocation density around yield-drop in the UFG specimen quickly increased. ECCI observations revealed the nucleation of deformation twins and stacking faults from grain boundaries in the UFG specimen around yielding. Although it had been conventionally reported that the grain refinement suppresses deformation twinning in FCC metals and alloys, the number density of deformation twins in the 0.79 μm grain-sized specimen was much higher than that in the specimens with grain sizes of 4.5 μm and 15.4 μm. The unusual change of yielding behavior from continuous to discontinuous manner by grain refinement could be understood on the basis of limited number of free dislocations in each ultrafine grain. The results indicated that the scarcity of free dislocations in the recrystallized UFG specimens changed the deformation and twinning mechanisms in the TWIP steel.

Effect of Shock Loading on the Microstructure of Uniloy 326

1974 ◽  
Vol 32 ◽  
pp. 504-505
Author(s):  
K. P. Staudhammer ◽  
L. E. Murr
Keyword(s):  
Grain Size ◽  
Shock Loading ◽  
Current Investigation ◽  
Two Phase ◽  
05 C ◽  
Shock Deformation ◽  
Heat Treated

The effect of shock loading on a variety of steels has been reviewed recently by Leslie. It is generally observed that significant changes in microstructure and microhardness are produced by explosive shock deformation. While the effect of shock loading on austenitic, ferritic, martensitic, and pearlitic structures has been investigated, there have been no systematic studies of the shock-loading of microduplex structures.In the current investigation, the shock-loading response of millrolled and heat-treated Uniloy 326 (thickness 60 mil) having a residual grain size of 1 to 2μ before shock loading was studied. Uniloy 326 is a two phase (microduplex) alloy consisting of 30% austenite (γ) in a ferrite (α) matrix; with the composition.3% Ti, 1% Mn, .6% Si,.05% C, 6% Ni, 26% Cr, balance Fe.

Parasitic aware impedance matching techniques for RF amplifiers

2011 ◽  
Vol 70 (1) ◽  
pp. 91-102 ◽  
Author(s):  
K. Dasgupta ◽  
A. Dutta ◽  
T. K. Bhattacharyya
Keyword(s):  
Impedance Matching ◽  
Rf Amplifiers ◽  
Matching Techniques

scholarly journals Defect and Damage Evolution Quantification in Dynamically-Deformed Metals Using Orientation-Imaging Microscopy

2010 ◽  
Vol 654-656 ◽  
pp. 2297-2302 ◽  
Author(s):  
George T. Gray III ◽  
Veronica Livescu ◽  
Ellen K. Cerreta
Keyword(s):  
Detonation Wave ◽  
Damage Evolution ◽  
Shock Loading ◽  
Volume Fraction ◽  
Orientation Imaging Microscopy ◽  
Electron Back Scatter Diffraction ◽  
Orientation Imaging ◽  
Deformation Twins

Orientation-imaging microscopy offers unique capabilities to quantify the defects and damage evolution occurring in metals following dynamic and shock loading. Examples of the quantification of the types of deformation twins activated, volume fraction of twinning, and damage evolution as a function of shock loading in Ta are presented. Electron back-scatter diffraction (EBSD) examination of the damage evolution in sweeping-detonation-wave shock loading to study spallation in Cu is also presented.

scholarly journals Impedance Matching Techniques for Microstrip Patch Antenna

2017 ◽  
Vol 10 (28) ◽  
pp. 1-16 ◽  
Author(s):  
Sonia Sharma ◽  
C. C. Tripathi ◽  
Rahul Rishi ◽  
◽  
◽  
...  
Keyword(s):  
Patch Antenna ◽  
Impedance Matching ◽  
Microstrip Patch Antenna ◽  
Microstrip Patch ◽  
Matching Techniques

scholarly journals Deformation twinning and the role of amino acids and magnesium in calcite hardness from molecular simulation

2015 ◽  
Vol 17 (31) ◽  
pp. 20178-20184 ◽  
Author(s):  
A. S. Côté ◽  
R. Darkins ◽  
D. M. Duffy
Keyword(s):  
Molecular Dynamics ◽  
Amino Acids ◽  
Molecular Simulation ◽  
Elastic Properties ◽  
Deformation Twinning ◽  
Pure Crystal ◽  
Classical Molecular Dynamics ◽  
Deformation Twins

We employ classical molecular dynamics to calculate elastic properties and to model the nucleation and propagation of deformation twins in calcite, both as a pure crystal and with magnesium and aspartate inclusions.

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