Defect Structures of Intermetallic FeRh Alloys Induced by High-Speed Deformation

2002 ◽  
Vol 753 ◽  
Author(s):  
Yasunori Kibata ◽  
Fuminobu Hori ◽  
Ryuichiro Oshima ◽  
Masao Komatsu ◽  
Michio Kiritani
Keyword(s):  
Phase Transition ◽  
High Speed ◽  
Strain Rates ◽  
Doppler Broadening ◽  
Defect Structures ◽  
Impact Compression ◽  
High Speed Impact ◽  
Xrd And Tem ◽  
Coincidence Doppler Broadening

ABSTRACTIn order to study the role of vacancy-type defects in the unique deformati on-induced phase transition mechanisms of B2-L10 and B2-A1 of intermetallic compound Fe-Rh alloys, high-speed impact compression deformation has been carried out. Induced phases and substructures were examined by XRD and TEM. The relation between the phase transitions and vacancy-type defects was investigated by the positron annihilation Coincidence Doppler Broadening (CDB) method. The results showed that intermixed phases of L10 and A1 were always formed in the B2 phase, and the vacancy concentrations were rather decreased in the specimens deformed by higher strain rates, suggesting that vacancies were more consumed by the phase transition to A1 structure.

High-speed impact compression testing of metals

1980 ◽  
Vol 12 (2) ◽  
pp. 210-213
Author(s):  
G. V. Stepanov ◽  
V. V. Astanin
Keyword(s):  
High Speed ◽  
Compression Testing ◽  
Impact Compression ◽  
High Speed Impact

Compression Tests of High Strength Steels

2008 ◽  
Vol 59 ◽  
pp. 293-298
Author(s):  
Vaclav Mentl ◽  
Josef Bystricky
Keyword(s):  
Mechanical Properties ◽  
Mechanical Testing ◽  
High Speed ◽  
Dynamic Compression ◽  
Testing Machine ◽  
High Strength Steels ◽  
High Strength ◽  
Strain Rates ◽  
Compression Tests ◽  
Impact Compression

Mathematical modelling and virtual testing of components and structures represent a useful and economic tool for design and safety assessment. The basic mechanical properties which can be found in material standards are not relevant in cases where the real service conditions differ from those applied during standardised testing. Thus e.g. mechanical behaviour at higher strain rates can be interesting for the car components when the simulation of crash situations is used during structure development. The dynamic compression tests are usually performed by means of drop towers, by means of high speed hydraulic testing machines or Hopkinson bar method. At the Mechanical Testing Laboratory of the SKODA Research Inst. in Pilsen, Czech Republic, an instrumentation of Charpy pendulum testing machine was realised in order that it was possible to perfom dynamic compression tests, [1], and the compatibility of obtained results in comparison with traditional impact compression tests was verified within the round–robin carried out by TC5 ESIS Sub-Committee on “Mechanical Testing at Intermediate Strain Rates“, [2]. A new striking tup and load measurement system were designed and callibrated. At the same time, a new software was developed which makes it possible to evaluate the test force-deformation record. The goal of this study was 1. to check the possibility of compression testing of high strength materilas by mens of Charpy pendulum, and 2. to study the strain rate influence on basic mechanical properties.

scholarly journals Size Effects of Brittle Particles in Aerosol Deposition—Molecular Dynamics Simulation

2021 ◽  
Vol 30 (3) ◽  
pp. 503-522 ◽  
Author(s):  
Bahman Daneshian ◽  
Frank Gaertner ◽  
Hamid Assadi ◽  
Daniel Hoeche ◽  
Wolfgang Weber ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Inelastic Deformation ◽  
High Speed ◽  
Aerosol Deposition ◽  
Heat Diffusion ◽  
Dynamics Simulation ◽  
Impact Behavior ◽  
High Speed Impact ◽  
The Impact

AbstractUp to now, the role of particle sizes on the impact behavior of ceramic particles in aerosol deposition not yet fully understood. Hence, with the aim to supply a more general understanding, modeling series of low strain rate compression and high-speed impact were performed by molecular dynamics on single-crystalline particles in sizes of 10-300 nm that are tuned to match mechanical properties of TiO2-anatase. The modeling results reveal that particles with original diameter of 25-75 nm exhibit three different impact behaviors that could be distinguished as (i) rebounding, (ii) bonding and (iii) fragmentation, depending on their initial impact velocity. In contrast, particles larger than 75 nm do not exhibit the bonding behavior. Detailed stress and strain field distributions reveal that combination of “localized inelastic deformation” along the slip systems and “shear localization” cause bonding of the small and large particles to the substrate. The analyses of associated temperature rise by the inelastic deformation revealed that heat diffusion at these small scales depend on size. Whereas small particles could reach a rather homogeneous temperature distribution, the evolved heat in the larger ones keeps rather localized to areas of highest deformation and may support deformation and the formation of dense layers in aerosol deposition.

scholarly journals Effect of high-speed impact compression on natural aging and subsequent artificial aging of a 6061 aluminum alloy

2015 ◽  
Vol 65 (12) ◽  
pp. 617-621
Author(s):  
Tomo Ogura ◽  
Keitaro Horikawa ◽  
Yuki Kitani ◽  
Mami Mihara ◽  
Seongnyeong Kim ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Artificial Aging ◽  
Natural Aging ◽  
Impact Compression ◽  
6061 Aluminum Alloy ◽  
High Speed Impact

scholarly journals Effect of High-Speed Impact Compression on Natural Aging and Subsequent Artificial Aging of a 6061 Aluminum Alloy

2016 ◽  
Vol 57 (8) ◽  
pp. 1282-1286
Author(s):  
Tomo Ogura ◽  
Keitaro Horikawa ◽  
Yuki Kitani ◽  
Mami Miara ◽  
SeongNyeong Kim ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
Artificial Aging ◽  
Natural Aging ◽  
Impact Compression ◽  
6061 Aluminum Alloy ◽  
High Speed Impact

EMPLOYING IMPACT TO INDUCE ULTRA-FINE GRAINS IN OXYGEN-FREE PURE COPPER

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1103-1110
Author(s):  
M. GONG ◽  
V. P. W. SHIM ◽  
L. M. YANG ◽  
F. CHEN
Keyword(s):  
High Speed ◽  
Bulk Material ◽  
Pure Copper ◽  
High Rate ◽  
Dislocation Loops ◽  
Boundary Slip ◽  
Impact Compression ◽  
Fine Grained ◽  
High Speed Impact ◽  
Dislocation Movement

An experimental investigation is undertaken to examine the possibility of producing ultra-fine grained bulk material through high-speed impact compression followed by annealing. A gas gun was employed to impose high-rate deformation on oxygen-free high-conductivity copper specimens to 90% strain. Samples were also quasi-statically compressed to identical final strains and similar heat treatment. Results show that after impact compression, grain boundaries widen and become less sharply defined, and many narrow twins are formed. For dynamic loading, grain boundary slip appears to accompany dislocation movement. Two dislocation characteristics were identified and the dislocation density was lower than that in samples compressed quasi-statically. Small dislocation loops were also observed. Portions of grains in specimens subjected to impact were mechanically broken into sizes less than 1 μm before annealing. The microhardness of impacted and statically compressed samples increased respectively by HV50 and HV60. After annealing at 190°C for 1 hour, ultra-fine grains with grain sizes ranging from 40∼200 nanometers were observed in impacted samples. This study highlights the potential of utilizing impact compression to produce bulk material with ultra-fine grains.

Influence of Sintering Temperature on Defects in Porous Silica Monoliths Studied by Positron Annihilation Techniques

2008 ◽  
Vol 607 ◽  
pp. 204-206 ◽  
Author(s):  
Yu Yang Huang ◽  
Chao Xiong ◽  
Yu Xin Wang ◽  
Yan Qiong Lu ◽  
Wen Deng
Keyword(s):  
Phase Transition ◽  
Organic Substance ◽  
Positron Lifetime ◽  
Sintering Temperature ◽  
Porous Silica ◽  
Doppler Broadening ◽  
Silica Monoliths ◽  
Ratio Curve ◽  
Doppler Broadening Spectra ◽  
Coincidence Doppler Broadening

Positron lifetime and coincidence Doppler broadening spectra for porous silica calcined at temperatures from 900 to 1500 oC have been measured. As the sintering temperatures increasing from 900 to 1000 oC, the height of the peaks of the ratio curves decrease, and the τ3 increases, which is due to the exclusion of the gas and the organic substance out of the cavities. As the sintering temperatures increasing from 1000 to 1250 oC, some of the defects were recovered, the grains of low quarts appearing and growing. This gives rise to the increase of the height of the peak of the ratio curve, and the decrease of lifetime (τ1,τ2 and τ3). As the sintering temperatures increasing from 1250 to 1500oC, the height of the peak of the ratio curve decreases, and the lifetime increases due to the phase transition of low quartz to cristobalite.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

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