Large strain work hardening in the alloy Al–1Mg–1Mn at low and intermediate deformation temperatures: experiments and modelling

2002 ◽  
Vol 324 (1-2) ◽  
pp. 244-250 ◽  
Author(s):  
B. Mülders ◽  
M. Zehetbauer ◽  
G. Gottstein ◽  
P. Les ◽  
E. Schafler
Keyword(s):  
Work Hardening ◽  
Large Strain ◽  
Intermediate Deformation

Influence of Processing Route on the Work-Hardening and Ductile Fracture of an AA6060 Aluminium Alloy

2014 ◽  
Vol 794-796 ◽  
pp. 284-289 ◽  
Author(s):  
Odd Sture Hopperstad ◽  
Ida Westermann ◽  
Ketill Olav Pedersen ◽  
Trond Furu ◽  
Tore Børvik
Keyword(s):  
Ductile Fracture ◽  
Aluminium Alloy ◽  
Work Hardening ◽  
Large Strain ◽  
Tensile Tests ◽  
Grain Structure ◽  
Processing Route ◽  
Stress Strain ◽  
Minimum Cross Section ◽  
Processing Step

Tensile tests on smooth and notched axisymmetric specimens were carried out to determine the large strain work-hardening curves and the ductile fracture characteristics of an AA6060 aluminium alloy for three different processing routes. The alloy was processed in three subsequent steps: 1) casting and homogenization, 2) extrusion, and 3) cold rolling and heat treatment to obtain a recrystallized grain structure. After each processing step, the material was tested after natural ageing for more than one week. A laser-based extensometer was used to continuously measure the average true strains to failure in the minimum cross-section of the specimens and the true stress-strain curves were calculated. Since these curves are influenced by necking, they do not represent the correct work-hardening of the material. Accordingly, finite element (FE) simulations of the tensile tests on the smooth axisymmetric specimens were conducted to determine the work-hardening curves to failure, using an optimization tool that interfaced with the nonlinear FE code and the experimental stress-strain curves as objectives. The microstructure of the alloy was characterized after the three processing steps by optical and scanning electron microscopy, and fractography was used to investigate the failure mechanisms.

scholarly journals Large strain hardening of magnesium containing in situ nanoparticles

2021 ◽  
Vol 10 (1) ◽  
pp. 1018-1030
Author(s):  
Zhongxue Feng ◽  
Yuhua Zhang ◽  
Jun Tan ◽  
Yuming Chen ◽  
Yiming Chen ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Work Hardening ◽  
High Strain ◽  
Large Strain ◽  
Plasma Sintering ◽  
Pile Up ◽  
Spark Plasma ◽  
Dislocation Cells

Abstract In this work, in situ magnesium-based composite composed of nanoscale magnesium oxide (MgO), prepared by spark plasma sintering, shows significant plasticity and high strain hardening. During the strain-hardening stage, the incremental work-hardening exponent shows drastic fluctuations due to the pile-up and release of dislocations. The dislocation pile-up at the interface makes it possible to form dislocation cells. Mixed dislocations can be generated within the cells surrounding the MgO particles, which can interact with the stress field and effectively hinder the movement of dislocations, leading to an increase in dislocation density. What is more, grain boundaries have higher elastic modulus and hardness, which may lead to the appearance of microcracks and eventually intergranular fractures. Our results may shed some light on understanding the role of MgO particles in influencing the mechanical properties of Mg alloys and Mg-based composites, especially in work hardening.

Large strain work hardening of aluminum alloys and the effect of mg in solid solution

2006 ◽  
Vol 37 (6) ◽  
pp. 2007-2013 ◽  
Author(s):  
Øyvind Ryen ◽  
Hans Ivar Laukli ◽  
Bjørn Holmedal ◽  
Erik Nes
Keyword(s):  
Solid Solution ◽  
Aluminum Alloys ◽  
Work Hardening ◽  
Large Strain

The Role of Microcracks in Large Plastic Deformation

1981 ◽  
Vol 103 (4) ◽  
pp. 431-436 ◽  
Author(s):  
L. H. S. Luong ◽  
R. H. Brown
Keyword(s):  
Plastic Deformation ◽  
Flow Stress ◽  
Work Hardening ◽  
Large Strain ◽  
Strain Rates ◽  
Compression Tests ◽  
Large Plastic Deformation ◽  
Negative Work ◽  
Compressive Stresses

This paper describes the results obtained from shear-compression tests carried out at low strain rates and at strain rates equivalent to those in a typical machining operation. These tests together with metallographic work are used to explain the influence of microcracks on the flow stress of work material. It is shown that the negative work-hardening effect observed at large strain deformation in the presence of compressive stresses is associated with the behavior of microcracks. A mechanism is proposed to account for this phenomenon.

scholarly journals Consequences of large strain anisotropic work-hardening in cold forging

2021 ◽  
Author(s):  
Felix Kolpak ◽  
Oliver Hering ◽  
A. Erman Tekkaya
Keyword(s):  
Work Hardening ◽  
Strain Path ◽  
Large Strain ◽  
Constitutive Models ◽  
Numerical Data ◽  
Tensile Tests ◽  
Cold Forging ◽  
Cold Forming ◽  
Process Forces ◽  
Multi Stage

AbstractThe influence of anisotropic work-hardening on the component properties and process forces in cold forging is investigated. The focus is on the material behaviour exhibited after strain path reversals. The work-hardening of three steels is characterized for large monotonic strains (equivalent strains up to 1.7) and subsequent strain path reversals (accumulated strains up to 2.5). Tensile tests on specimens extracted from rods forward extruded at room temperature reveal an almost linear work-hardening for all investigated steels. The application of compressive tests on extruded material gives insights into the non-monotonic work-hardening behaviour. All previously reported anisotropic work-hardening phenomena such as the Bauschinger effect, work-hardening stagnation and permanent softening are present for all investigated steels and intensify with the pre-strain. Experimental results of 16MnCrS5 were utilized to select constitutive models of increasing complexity regarding their capability to capture anisotropic work-hardening. The best fit between experimental and numerical data was obtained by implementation of a modified Yoshida-Uemori model, which is able to capture all observed anisotropic work-hardening phenomena. The constitutive models were applied in simulations of single- and multi-stage cold forming processes, revealing the significant effect of anisotropic hardening on the predicted component properties and process forces, originating in the process-intrinsic strain path reversals as well as in strain path reversals between subsequent forming stages. Selected results were validated experimentally.

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