scholarly journals Analysis and Characterization on Dynamic Recrystallization in Casting AZ31 Mg Alloys Under Plane Strain Compression

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 522
Author(s):  
Li Xu ◽  
Minghua Xiang ◽  
Jun Wang ◽  
Jun Zhang ◽  
Chenning Wang ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Plane Strain ◽  
Rate Sensitivity ◽  
Local Stress ◽  
Plane Strain Compression ◽  
Mg Alloys ◽  
Coarse Grained ◽  
Compression Tests

Studies on twinning, twin-induced dynamic recrystallization (TDRX), and their temperature and strain rate dependences are of considerable significance to the ultimate strength and plastic formability of the coarse-grained Mg alloys during severe plastic deformation. Plane strain compression tests were conducted on the parallelepiped samples of casting AZ31 Mg alloys. The twinning and recrystallization behaviors close to and away from the crack boundaries were characterized using electron backscatter diffraction. The results show: (1) with increasing strain rate for tests, the extension twin proliferates significantly. Due to the local stress concentration, the TDRX is more active in the area close to the crack tip and exhibits the positive strain-rate sensitivity as twinning; (2) the TDRX is not only stress-favored but also closely links to the temperature. However, the TDRX is not utterly proportional to the temperature. Compared to 400 °C, 300 °C is more beneficial to the TDRX, achieving the higher strength and plastic deformability. The main reason is that the higher strain-hardening rate and flow stress at the higher strain rate and lower temperature motivates the transformation from twinning to the fine twin-walled grains more efficiently, and the stress-favored TDRX is crucial to refine grains and continue plastic deformation for the casting Mg alloys with coarse grains.

Texture Formation Behaviour during High-Temperature Plane Strain Compression Deformation in AZ91 Magnesium Alloy

2018 ◽  
Vol 941 ◽  
pp. 1198-1202
Author(s):  
Dong Keun Han ◽  
Min Soo Park ◽  
Han Sang Kwon ◽  
Kwon Hoo Kim
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Plane Strain ◽  
Texture Evolution ◽  
Plane Strain Compression ◽  
Deformation Condition ◽  
Rolled Plate ◽  
Pole Density ◽  
Texture Formation ◽  
Compression Tests

In previous study, it was investigated texture formation behaviour of high-temperature plane strain compression test at 723K, under a strain rate of 5.0. It was found that the main texture component and it was sharpness vary depending on deformation conditions. To clarify the characteristic of texture formation behaviour, it is necessary to investigate at various deformation condition. Therefore, in this study, is investigating the influence or texture formation behaviour and strain, strain rate at 673K. Three kinds of specimens with different initial textures were machined out from a rolled plate having a <0001> texture. The plane strain compression tests were conducted at a temperature 673K, and a strain rate of 5.0, with strain between-0.4 to-1.0. After compression tests, the specimens were immediately quenched in oil. The texture evolution was conducted by the Schulz reflection method using Cu Kα radiation and EBSD. Before the deformation, {0001} of specimen A was accumulated in the center of pole figure. The {0001} of specimen B was accumulated at the RD direction. The {0001} of specimen C was accumulated TD direction. As a result, work softening is observed in all the cases at the true stress – true strain curve for three types of specimens. After deformation, the maximum pole density of increases with increasing strain. In this study, it was found that the stable orientation was (0001)<100> and (0001)<110> during deformation.

Formability of Explosive Welded Mg/Al Bimetallic Bar

2016 ◽  
Vol 716 ◽  
pp. 114-120 ◽  
Author(s):  
Sebastian Mróz ◽  
Piotr Szota ◽  
Teresa Bajor ◽  
Andrzej Stefanik
Keyword(s):  
Plastic Deformation ◽  
Strain Rate ◽  
Process Parameters ◽  
Metal Forming ◽  
Explosive Welding ◽  
Physical Modelling ◽  
Main Process ◽  
Compression Tests ◽  
Welding Method

The paper presents the results of physical modelling of the plastic deformation of the Mg/Al bimetallic specimens using the Gleeble 3800 simulator. The plastic deformation of Mg/Al bimetal specimens characterized by the diameter to thickness ratio equal to 1 was tested in compression tests. The aim of this work was determination of the range of parameters as temperature and strain rate that mainly influence on the plastic deformation of Mg/Al bars during metal forming processes. The tests were carried out for temperature range from 300 to 400°C for different strain rate values. The stock was round 22.5 mm-diameter with an Al layer share of 28% Mg/Al bars that had been produced using the explosive welding method. Based on the analysis of the obtained testing results it has been found that one of the main process parameters influencing the plastic deformation the bimetal components is the initial stock temperature and strain rate values.

Characteristics of the Deformed and Recrystallised Grains Obtained after Hot Plane Strain Compression of a Model Fe-30wt%Ni Alloy

2004 ◽  
Vol 467-470 ◽  
pp. 21-26 ◽  
Author(s):  
F. Bai ◽  
P. Cizek ◽  
Eric J. Palmiere ◽  
Mark W. Rainforth
Keyword(s):  
Plane Strain ◽  
Crystallographic Texture ◽  
Hot Deformation ◽  
Electron Backscatter Diffraction ◽  
Orientation Dependence ◽  
Plane Strain Compression ◽  
Formation Mechanisms ◽  
Subgrain Structure ◽  
Compression Tests ◽  
Texture Characteristics

The development of physically-based models of microstructural evolution during hot deformation of metallic materials requires knowledge of the grain/subgrain structure and crystallographic texture characteristics over a range of processing conditions. A Fe-30wt%Ni based alloy, retaining a stable austenitic structure at room temperature, was used for modelling the development of austenite microstructure during hot deformation of conventional carbon-manganese steels. A series of plane strain compression tests was carried out at a temperature of 950 °C and strain rates of 10 s-1 and 0.1 s-1 to several strain levels. Evolution of the grain/subgrain structure and crystallographic texture was characterised in detail using quantitative light microscopy and highresolution electron backscatter diffraction. Crystallographic texture characteristics were determined separately for the observed deformed and recrystallised grains. The subgrain geometry and dimensions together with the misorientation vectors across sub-boundaries were quantified in detail across large sample areas and the orientation dependence of these characteristics was determined. Formation mechanisms of the recrystallised grains were established in relation to the deformation microstructure.

Critical Strain for the Initiation of Dynamic Recrystallization in a Ni-Fe Base Alloy

2004 ◽  
Vol 449-452 ◽  
pp. 577-580
Author(s):  
Young Sang Na ◽  
Young Mok Rhyim ◽  
J.Y. Lee ◽  
Jae Ho Lee
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Critical Strain ◽  
Base Alloy ◽  
Strain Rate Range ◽  
Boundary Phase ◽  
Alloy 718 ◽  
Compression Tests ◽  
Temperature Range ◽  
Critical Strains

In order to quantitatively analyze the critical strain for the initiation of dynamic recrystallization in Ni-Fe-based Alloy 718, a series of uniaxial compression tests was conducted in the temperature range 927°C - 1066°C and the strain rate range 5 x 10-4s-1- 5 s-1with varying initial grain size. The critical strains were graphically determined based on one parameter approach and microscopically confirmed. The effect of γ'' (matrix-hardening phase) and δ (grain boundary phase)on the critical strain was simply discussed. The constitutive model for the critical strain of Alloy 718 was constructed using the experimental data obtained from the higher strain rate and the temperature range between 940°C and 1040°C.

scholarly journals Hot Deformation Behavior of a Ni-Based Superalloy with Suppressed Precipitation

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 605
Author(s):  
Franco Lizzi ◽  
Kashyap Pradeep ◽  
Aleksandar Stanojevic ◽  
Silvana Sommadossi ◽  
Maria Cecilia Poletti
Keyword(s):  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Strain Rates ◽  
Compression Tests ◽  
Deformation Bands ◽  
Stress Softening ◽  
Relative Stress ◽  
The Matrix ◽  
Thermomechanical Processes

Inconel®718 is a well-known nickel-based super-alloy used for high-temperature applications after thermomechanical processes followed by heat treatments. This work describes the evolution of the microstructure and the stresses during hot deformation of a prototype alloy named IN718WP produced by powder metallurgy with similar chemical composition to the matrix of Inconel®718. Compression tests were performed by the thermomechanical simulator Gleeble®3800 in a temperature range from 900 to 1025 °C, and strain rates scaled from 0.001 to 10 s−1. Flow curves of IN718WP showed similar features to those of Inconel®718. The relative stress softening of the IN718WP was comparable to standard alloy Inconel®718 for the highest strain rates. Large stress softening at low strain rates may be related to two phenomena: the fast recrystallization rate, and the coarsening of micropores driven by diffusion. Dynamic recrystallization grade and grain size were quantified using metallography. The recrystallization grade increased as the strain rate decreased, although showed less dependency on the temperature. Dynamic recrystallization occurred after the formation of deformation bands at strain rates above 0.1 s−1 and after the formation of subgrains when deforming at low strain rates. Recrystallized grains had a large number of sigma 3 boundaries, and their percentage increased with strain rate and temperature. The calculated apparent activation energy and strain rate exponent value were similar to those found for Inconel®718 when deforming above the solvus temperature.

scholarly journals Small-Scale Plastic Deformation of Nanocrystalline High Entropy Alloy

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 889 ◽  
Author(s):  
Sanghita Mridha ◽  
Mageshwari Komarasamy ◽  
Sanjit Bhowmick ◽  
Rajiv Mishra ◽  
Sundeep Mukherjee
Keyword(s):  
Plastic Deformation ◽  
Rate Sensitivity ◽  
Small Scale ◽  
High Entropy Alloy ◽  
Compression Tests ◽  
High Entropy ◽  
Grain Sizes ◽  
Plastic Deformation Behavior ◽  
High Strain Rate Sensitivity ◽  
Widespread Interest

High entropy alloys (HEAs) have attracted widespread interest due to their unique properties at many different length-scales. Here, we report the fabrication of nanocrystalline (NC) Al0.1CoCrFeNi high entropy alloy and subsequent small-scale plastic deformation behavior via nano-pillar compression tests. Exceptional strength was realized for the NC HEA compared to pure Ni of similar grain sizes. Grain boundary mediated deformation mechanisms led to high strain rate sensitivity of flow stress in the nanocrystalline HEA.

Numerical Analysis of Plane-Strain Tension Test for Rate-Dependent Solids

1992 ◽  
Vol 59 (3) ◽  
pp. 485-490 ◽  
Author(s):  
P. Tugˇcu
Keyword(s):  
Numerical Analysis ◽  
Strain Rate ◽  
Plane Strain ◽  
Rate Sensitivity ◽  
Tension Test ◽  
Engineering Strain ◽  
Plane Strain Tension ◽  
Rate Dependent ◽  
Strain And Strain Rate ◽  
Strain Rate Hardening

The plane-strain tension test is analyzed numerically for a material with strain and strain-rate hardening characteristics. The effect of the prescribed rate of straining is investigated for an additive logarithmic description of the material strain-rate sensitivity. The dependency to the imposed strain rate so introduced is shown to have a significant effect on several features of the load-elongation curve such as the attainment of the load maximum, the onset of localization, and the overall engineering strain.

An Investigation of the Dynamic Recrystallisation Behaviour of Magnesium AZ31 Alloy at 450°C Using Plane Strain Compression Testing as a Tool

2012 ◽  
Vol 715-716 ◽  
pp. 164-169
Author(s):  
Bradley P. Wynne ◽  
R. Bhattacharya ◽  
Bruce Davis ◽  
W.M. Rainforth
Keyword(s):  
Strain Rate ◽  
Plane Strain ◽  
Testing Machine ◽  
Az31 Alloy ◽  
Plane Strain Compression ◽  
Strain Rates ◽  
Basal Texture ◽  
Magnesium Az31 ◽  
Dynamic Recrystallisation ◽  
Double Hit

The dynamic recrystallisation (DRX) behaviour of magnesium AZ31 is investigated using a plane strain compression (PSC) testing machine at 450°C. The variables included strain rate, double hit including intermittent anneal and double hits with different strain rate at each hit. The alloy shows higher peak stress and strain with increasing strain rates. Predominant basal texture with different intensities are observed at different strain rates. The annealing treatment between double tests leads to strong basal texture. Reversal of strain rate during double hit results in similar flow curves. This shows that in AZ31 alloy, DRX mechanism is independent of the initial microstructure and only depends on the test condition viz. temperature, strain rate and total equivalent strain.

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