Constrained Deformation of TiAl PST Crystals

2009 ◽  
Vol 1225 ◽  
Author(s):  
Kengo Goto ◽  
Kyosuke Kishida ◽  
Haruyuki Inui
Keyword(s):  
Deformation Behavior ◽  
Lamellar Structure ◽  
Early Stage ◽  
Strain Condition ◽  
Tem Analysis ◽  
Strain Behavior ◽  
Strain Components ◽  
Macroscopic Deformation ◽  
Constrained Deformation ◽  
Deformation Modes

AbstractTiAl polysynthetically twinned (PST) crystals were deformed under plane strain condition, in which the anisotropic macroscopic deformation of PST crystals is restricted with a channel die, in order to clarify the deformation behavior of TiAl/Ti3Al lamellar structure under constraint conditions. TEM analysis of deformation modes together with the Taylor analysis reveals that all TiAl orientation variants deform to yield the relaxed-constraint-type plastic strain, where three shear strain components are not zero for each TiAl variant but are macroscopically compensated to zero by the existence of twin-related TiAl lamellae at the early stage of deformation. The Taylor analysis assuming the relaxed constraint conditions is found to be adaptable for predicting the operative deformation modes in TiAl at the early stage of deformation and also for correlating quantitatively the stress-strain behavior of PST crystals under external constraint with those under the unconstraint condition.

Improving the GBT-based buckling analysis of restrained cold-formed steel members by considering constrained deformation modes

2021 ◽  
Vol 165 ◽  
pp. 107928
Author(s):  
Heitor F. Araujo ◽  
Cilmar Basaglia ◽  
Dinar Camotim ◽  
Thiago G. da Silva
Keyword(s):  
Buckling Analysis ◽  
Steel Members ◽  
Cold Formed Steel ◽  
Constrained Deformation ◽  
Deformation Modes

scholarly journals AFM In-situ Bending Test on Deformation Behavior of Polyethylene Lamellar Structure

2004 ◽  
Vol 53 (12) ◽  
pp. 1359-1364 ◽  
Author(s):  
Kisaragi YASHIRO ◽  
Masayuki KANAI ◽  
Yoshihiro TOMITA
Keyword(s):  
Deformation Behavior ◽  
Lamellar Structure ◽  
Bending Test

Hot deformation behavior and processing maps of Ti–6Al–4V alloy with starting fully lamellar structure

2018 ◽  
Vol 33 (22) ◽  
pp. 3677-3688 ◽  
Author(s):  
Wenjing Zhang ◽  
Hua Ding ◽  
Jingwei Zhao ◽  
Bo Yang ◽  
Wenjing Yang
Keyword(s):  
Hot Deformation ◽  
Deformation Behavior ◽  
Lamellar Structure ◽  
Processing Maps ◽  
Hot Deformation Behavior ◽  
Image Position ◽  
Fully Lamellar

Abstract

Microstructure Evolution of Near Gamma TiAl Intermetallic under Tensile Impact Loadings at High Temperatures

2010 ◽  
Vol 146-147 ◽  
pp. 1553-1556
Author(s):  
Yu Wang ◽  
Xiang Zan ◽  
Yue Hui He ◽  
Yang Wang
Keyword(s):  
Strain Rate ◽  
Microstructure Evolution ◽  
Deformation Mode ◽  
Deformation Twinning ◽  
Stacking Fault ◽  
Effect Of Temperature ◽  
Dislocation Slip ◽  
Tem Analysis ◽  
Dynamic Loadings ◽  
Deformation Modes

The effect of temperature and strain rate on the mechanical behavior and microstructure evolution of Near Gamma Ti-46.5Al-2Nb-2Cr (NG TiAl) was investigated at temperatures ranging from room temperatures to 840 under strain rates of 0.001, 320, 800 and 1350s-1. The TEM analysis indicated that deformation twinning and stacking fault are the main deformation modes under dynamic loadings and dislocation slip is another important deformation mode under quasi-static loadings. The density of deformation twinning and/or stacking fault increases with the increased temperature and strain rate.

IMAGE ANALYSIS BASED FINITE STRAIN MEASUREMENT OF LOCAL DEFORMATION UNDER UNIAXIAL LOAD USING NATURAL STRAIN

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Yasuyuki Kato
Keyword(s):  
Image Analysis ◽  
Strain Measurement ◽  
Finite Strain ◽  
Local Deformation ◽  
Strain Theory ◽  
Strain Behavior ◽  
Natural Strain ◽  
Strain Components ◽  
Shearing Strain ◽  
Local Deformations

This paper describes the effectiveness of image analysis based on the Natural Strain theory for measuring the finite strain. Since the additive law of strain on an identical line element can be satisfied and the rigid body rotation can clearly be removed from the shearing strain components, the Natural Strain theory is significantly effective for representing the stress-strain behavior under large elasto-plastic deformation. In this study, the strain measurements under large deformation are conducted by making use of such merits into the image analysis. In our previous studies, in order to verify the effectiveness of this method, the results of strain measurement by image analysis have been compared with the results of conventional strain measurement based on the displacement meter. Consequently, since the results of both measurements almost coincide, the validity of this image analysis has been confirmed. However, these experiments were limited to uniform deformation fields, although in the range of finite deformation. Hence, as for the local deformation, the detailed measurements have not been carried out yet in our previous study. So, in this paper, the local deformations generated under uniaxial tension and simple shear are investigated as the fundamental research. Especially, the progress of local deformations is revealed by comparing the measured values of upper and middle positions in the specimen.

Deformation Modes and Anomalous Strengthening of Ni3X -Type Intermetallic Compounds with the Geometrically Close-Packed Structure

2005 ◽  
Vol 502 ◽  
pp. 145-150 ◽  
Author(s):  
Yukichi Umakoshi ◽  
Koji Hagihara ◽  
Takayoshi Nakano
Keyword(s):  
Plastic Deformation ◽  
Crystal Structures ◽  
Intermetallic Compounds ◽  
Deformation Behavior ◽  
Deformation Characteristics ◽  
Close Packed Structure ◽  
Plastic Deformation Behavior ◽  
Packed Structure ◽  
Deformation Modes

Plastic deformation behavior including anomalous strengthening of Ni3X-type compounds with D019, D0a and D024 structure were examined and summarized, focusing on the correlation between deformation characteristics and features of their crystal structures.

Modeling swelling–shrinkage behavior of compacted expansive soils during wetting–drying cycles

2015 ◽  
Vol 52 (6) ◽  
pp. 783-794 ◽  
Author(s):  
Gang Wang ◽  
Xing Wei
Keyword(s):  
Deformation Behavior ◽  
Early Stage ◽  
Expansive Soils ◽  
Level Structure ◽  
Shrinkage Strain ◽  
Model Parameters ◽  
Microstructural Parameters ◽  
Phenomenological Perspective ◽  
The Difference ◽  
Reversible Component

This paper presents a straightforward approach for modelling volume change behavior of expansive soils during wetting–drying cycles. The swelling–shrinkage strain of expansive soils induced by cyclic wetting and drying was decomposed with distinctive physical background into a reversible component, which shows a synchronous change with the cyclic change of suction, and an irreversible component, which is generated mainly in the early stage of the wetting–drying process. The mechanisms of the two swelling–shrinkage strain components can be well explained through the double-level structure of expansive soils and its evolution with mechanical and hydraulic loading. The reversible component originates from the reversible deformation behavior of aggregates, and primarily depends on current suction or water content. The irreversible component is associated with the irreversible change of macrostructure, reflecting the difference in soil structures at current state and the equilibrium state. A practical constitutive model was proposed for compacted expansive clays from a global and phenomenological perspective. The model parameters can be calibrated with observed macroscopic deformation behavior without measuring microstructural parameters. The performance of the presented model was validated by simulating cyclic suction-controlled tests as well as an alternately soaked and dried test with irregular amplitudes of suctions.

The Rate (Time)-Dependent Mechanical Behavior of the PMR-15 Thermoset Polymer at 316°C: Experiments and Modeling

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
M. B. Ruggles-Wrenn ◽  
O. Ozmen
Keyword(s):  
Experimental Data ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Inelastic Deformation ◽  
Rate Sensitivity ◽  
Experimental Program ◽  
Strain Rates ◽  
Neat Resin ◽  
Strain Behavior ◽  
Thermoset Polymer

The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at 316°C. The experimental program was designed to explore the influence of strain rate on tensile loading, unloading, and strain recovery behaviors. In addition, the effect of the prior strain rate on the relaxation response of the material, as well as on the creep behavior following strain-controlled loading were examined. Positive, nonlinear strain rate sensitivity is observed in monotonic loading. The material exhibits nonlinear, “curved” stress-strain behavior during unloading at all strain rates. The recovery of strain at zero stress is strongly influenced by the prior strain rate. The prior strain rate also has a profound effect on relaxation behavior. Likewise, creep response is significantly influenced by the prior strain rate. The experimental data are modeled with the viscoplasticity theory based on overstress (VBO). The comparison with experimental data demonstrates that the VBO successfully predicts the inelastic deformation behavior of the PMR-15 polymer under various test histories at 316°C.

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