A Novel Severe Plastic Deformation Process for Shear Deformation and Grain Refinement of Bulk Materials

2013 ◽  
Vol 829 ◽  
pp. 15-19 ◽  
Author(s):  
Mehdi Montazeri-Pour ◽  
Mohammad Habibi-Parsa
Keyword(s):  
Deformation Process ◽  
Metal Flow ◽  
Metallic Materials ◽  
Plastic Shear ◽  
Bulk Materials ◽  
Microstructure Characteristics ◽  
Plastic Deformation Process ◽  
Plastic Shear Strain ◽  
Commercial Code ◽  
Simulation Results

A novel experimental technique called "Multi-Axial Incremental Shearing" (MAIS) is proposed to impose plastic shear strain to the bulk metallic materials. The evolution of strain during MAIS processing of AA1100 alloy has been studied by employing 3D finite element modeling. The commercial code DEFORM was used to analyze the deformation and evolution of the working load with rams displacement as the material passes through the die. Simulation results showed that a large amount of accumulative strain can be applied to the sample without change of its dimensions. In order to verify the metal flow and microstructure characteristics, Sn-1wt.% Bi alloy specimens as the representative of the soft metals have been deformed by MAIS process.

Study on Metal Forming by Macro-Micro Combine Numerical Analysis

2007 ◽  
Vol 340-341 ◽  
pp. 671-676
Author(s):  
Shao Rui Zhang ◽  
Da Yong Li ◽  
Zhong Wei Yin ◽  
Ying Hong Peng ◽  
Fei Zhou
Keyword(s):  
Metal Forming ◽  
Deformation Process ◽  
Metal Flow ◽  
Yield Function ◽  
Slip Systems ◽  
Crystallographic Slip ◽  
Deformation Properties ◽  
Simulation Results ◽  
True Relation ◽  
Anisotropy Coefficients

It has long been found that the crystal orientations would induce macroscopic anisotropy during deformation process, and then affect the deformation properties of sheet metal. So it is very important to find the true relation between texture distribution and macroscopic anisotropy. In this paper, the anisotropy coefficients of the yield function are fitted by Taylor factor and crystal plastic model. Metal flow is assumed to occur by crystallographic slip on given slip systems within each crystal. Then this simulation results are compared with those of microscopic crystal plastic method.

Design and Implementation of a Device for Nanostructuring of Metallic Materials by Multiaxial Forging Method

2014 ◽  
Vol 657 ◽  
pp. 193-197 ◽  
Author(s):  
Alin Marian Cazac ◽  
Costică Bejinariu ◽  
Iulian Ionita ◽  
Stefan Lucian Toma ◽  
Cosmin Rodu
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Deformation Process ◽  
Extraction System ◽  
Metallic Materials ◽  
Severe Plastic Deformation Process ◽  
Design And Implementation ◽  
Discontinuous Process ◽  
Plastic Deformation Process ◽  
High Level

This paper presents materialization through a device of severe plastic deformation process by multiaxial forging. In essence, by design, the device includes a board reinforced with fretting rings where the severe plastic deformation takes place and an assembly, punch-counterpunch that transmits the force from the source and performs multiaxial forging as a discontinuous process. The device has a high level of universality and has the following advantages: contains an extraction system of deformed blank from the active fretted broad; ensures workpiece centering into place of active plate, contains a system for measuring the strength of forging; can be used on any type of press.

Numerical analysis of plastic deformation evolution into metallic materials during spherical indentation process

2009 ◽  
Vol 24 (3) ◽  
pp. 1270-1278 ◽  
Author(s):  
M. Beghini ◽  
L. Bertini ◽  
V. Fontanari ◽  
B.D. Monelli
Keyword(s):  
Plastic Deformation ◽  
Friction Coefficient ◽  
Deformation Process ◽  
Indentation Depth ◽  
Spherical Indentation ◽  
Plastic Strains ◽  
Metallic Materials ◽  
Contact Conditions ◽  
Plastic Deformation Process ◽  
Load Indentation

The present paper deals with the plastic deformation process into metallic materials occurring in the subindenter region during the loading cycle of spherical indentation test. Load–indentation-depth curve and plastic strains field evolution in the region beneath the indenter are examined using finite element analysis (FEA). The FE model was set up and validated by comparison with experimental spherical indentations carried out on two different materials (Al6082-T6, AISI H13) under four different friction conditions, corresponding to friction coefficients equal to 0.0, 0.1, 0.3, and 0.5. It is confirmed that friction effects on load–indentation-depth curves are negligible for the investigated penetration depths, whereas the plastic deformation process is affected by the contact conditions. The investigation shows that, although the L–h curve is not affected by the contact conditions up to medium values of the penetration depth, remarkable effects are produced in the overall plastic core under the indenter. A strong correlation between plastic strains field and friction coefficient is especially observed at low values of this parameter, whereas a saturation of the phenomena is found for medium-high values of the friction coefficient.

A Study of Metal Flow Ahead of Tool Face With Large Negative Rake Angle

1982 ◽  
Vol 104 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Y. Kita ◽  
M. Ido ◽  
N. Kawasaki
Keyword(s):  
Deformation Process ◽  
Metal Flow ◽  
Close Relation ◽  
Rake Angle ◽  
High Quality ◽  
Flow Lines ◽  
Stress Changes ◽  
Chip Formation Mechanism ◽  
Maximum Increment ◽  
Side Flow

Although the chip formation mechanism by a tool having a large negative rake angle is not well known, it is very important to make the process clear in order to get high quality in finished surfaces. In this paper, the behavior of material ahead of a tool face with a large negative rake angle is examined by means of low speed machining on lead. The deformation process of the material is investigated by the deformation study combining a finite element method with a grid line method. During cutting, the deformation process of grid lines which were drawn on the sides of testpieces was observed through a side glass which restricted the side flow of material. Cutting force was measured by a dynamometer consisting of an elongated octagonal ring with strain wire gages. As a result it was found that the shear stress on the slip line of maximum increment of shear strain is nearly constant, but the compressive stress changes along the line. It was concave near the top of cutting edge and convex near the surface of the test piece. The position of the change of polarity in the slope shifted depending on the rake angle of the tool. This phenomenon is considered to have close relation with the stagnant tip, which decides not only the size of chip, but also whether or not a chip will be formed. Flow lines of material and the deformed region ahead of tool faces with different negative rake angles were also obtained and they were compared with each other.

scholarly journals A Dislocation-Based Theory for the Deformation Hardening Behavior of DP Steels: Impact of Martensite Content and Ferrite Grain Size

2010 ◽  
Vol 2010 ◽  
pp. 1-16 ◽  
Author(s):  
Yngve Bergström ◽  
Ylva Granbom ◽  
Dirk Sterkenburg
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Deformation Process ◽  
Volume Fraction ◽  
High Energy ◽  
Martensite Content ◽  
Plastic Deformation Process ◽  
Deformation Hardening ◽  
Dp Steels ◽  
Ferrite Grain Size

A dislocation model, accurately describing the uniaxial plastic stress-strain behavior of dual phase (DP) steels, is proposed and the impact of martensite content and ferrite grain size in four commercially produced DP steels is analyzed. It is assumed that the plastic deformation process is localized to the ferrite. This is taken into account by introducing a nonhomogeneity parameter, f(ε), that specifies the volume fraction of ferrite taking active part in the plastic deformation process. It is found that the larger the martensite content the smaller the initial volume fraction of active ferrite which yields a higher initial deformation hardening rate. This explains the high energy absorbing capacity of DP steels with high volume fractions of martensite. Further, the effect of ferrite grain size strengthening in DP steels is important. The flow stress grain size sensitivity for DP steels is observed to be 7 times larger than that for single phase ferrite.

Numerical Simulation on Thixo-Forging of Magnesium Matrix Composite

2011 ◽  
Vol 189-193 ◽  
pp. 2535-2538 ◽  
Author(s):  
Hong Yan ◽  
Wen Xian Huang
Keyword(s):  
Numerical Simulation ◽  
Matrix Composite ◽  
Metal Flow ◽  
Magnesium Matrix Composite ◽  
Magnesium Matrix ◽  
Simulation Based ◽  
Prior Literature ◽  
Simulation Results ◽  
Computer Numerical Simulation ◽  
Good Agreement

The thixo-forging of magnesium matrix composite was analyzed with computer numerical simulation based on rigid viscoplastic finite element method. The constitutive model of SiCp/AZ61 composite was established in our prior literature. Behavior of metal flow and temperature field were obtained. The differences between traditional forging and thixo-forging processes were analyzed. Results indicated that thixo-forging was better in filling cavity than forging. Simulation results were good agreement with experimental ones.

Processing Dense Hetero-Nanostructured Metallic Materials for Improved Strength/Ductility Balance through High Strain Deformation and Electrical Current Assisted Sintering (ECAS)

2009 ◽  
Vol 633-634 ◽  
pp. 559-567 ◽  
Author(s):  
Thierry Grosdidier ◽  
Núria Llorca-Isern
Keyword(s):  
High Strain ◽  
Milled Powder ◽  
Electrical Current ◽  
Processing Parameters ◽  
Metallic Materials ◽  
Bulk Materials ◽  
Multi Scale ◽  
Field Assisted Sintering ◽  
Y2o3 Addition ◽  
Powder Metallurgy Route

This paper has examined some recent findings concerning the processing of fully dense hetero-nanostructured materials (i.e. consisting of nano, ultrafine and micrometric grains) which can be produced by using the interplay between heavy deformation and recrystallization. By plastic deformation of bulk materials, an improved strength/ductility balance can be obtained directly by imparting high strain deformation (by ECAE) until the occurrence of recrystallization. Using a powder metallurgy route, the strong potential of electric field assisted sintering (ECAS) for producing multi-scale microstructures when a milled powder is used is also demonstrated. In this case, in addition to modify the classic processing parameters (time/temperature of ECAS), altering the nature of the milled powder - by Y2O3 addition during the milling stage - is also a good way to delay the onset of recrystallization and, thereby, increase the fraction of ultrafine grains.

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