Nanoscale deformation of multiaxially forged ultrafine-grained Mg-2Zn-2Gd alloy with high strength-high ductility combination and comparison with the coarse-grained counterpart

2018 ◽  
Vol 34 (2) ◽  
pp. 311-316 ◽  
Author(s):  
K. Li ◽  
V.S.Y. Injeti ◽  
P. Trivedi ◽  
L.E. Murr ◽  
R.D.K. Misra
Keyword(s):  
High Strength ◽  
Coarse Grained ◽  
High Ductility ◽  
Ultrafine Grained

scholarly journals Heterogeneous lamella structure unites ultrafine-grain strength with coarse-grain ductility

2015 ◽  
Vol 112 (47) ◽  
pp. 14501-14505 ◽  
Author(s):  
Xiaolei Wu ◽  
Muxin Yang ◽  
Fuping Yuan ◽  
Guilin Wu ◽  
Yujie Wei ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
High Strength ◽  
Back Stress ◽  
Coarse Grained ◽  
Ultrafine Grain ◽  
Asymmetric Rolling ◽  
Dislocation Hardening ◽  
Ultrafine Grained ◽  
Lamella Structure

Grain refinement can make conventional metals several times stronger, but this comes at dramatic loss of ductility. Here we report a heterogeneous lamella structure in Ti produced by asymmetric rolling and partial recrystallization that can produce an unprecedented property combination: as strong as ultrafine-grained metal and at the same time as ductile as conventional coarse-grained metal. It also has higher strain hardening than coarse-grained Ti, which was hitherto believed impossible. The heterogeneous lamella structure is characterized with soft micrograined lamellae embedded in hard ultrafine-grained lamella matrix. The unusual high strength is obtained with the assistance of high back stress developed from heterogeneous yielding, whereas the high ductility is attributed to back-stress hardening and dislocation hardening. The process discovered here is amenable to large-scale industrial production at low cost, and might be applicable to other metal systems.

Tailoring stacking fault energy for high ductility and high strength in ultrafine grained Cu and its alloy

2006 ◽  
Vol 89 (12) ◽  
pp. 121906 ◽  
Author(s):  
Y. H. Zhao ◽  
Y. T. Zhu ◽  
X. Z. Liao ◽  
Z. Horita ◽  
T. G. Langdon
Keyword(s):  
High Strength ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
High Ductility ◽  
Ultrafine Grained

Influence of Severe Plastic Deformation on Mechanical Properties of an AA5024 Alloy

2016 ◽  
Vol 879 ◽  
pp. 1317-1322 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Yuzbekova ◽  
Tatiana Lebedkina ◽  
Mikhail Lebyodkin ◽  
Rustam Kaibyshev
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Strength ◽  
Coarse Grained ◽  
Type B ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Elongation To Failure ◽  
Dislocation Strengthening

The paper reports on the effect of severe plastic deformation on mechanical properties of an Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (in wt. pct.) alloy processed by equal channel angular pressing followed by cold rolling (CR). The sheets of the 5024 alloy with coarse grained (CG) structure exhibited a yield stress (YS) near 410 MPa and an ultimate tensile strength (UTS) of 480 MPa, while the YS and UTS of this material with ultrafine-grained (UFG) structure increased to 530 and 560 MPa, respectively. On the other hand, the elongation to failure decreased by a factor of 2 and 4 after CR and CR following ECAP, respectively. It was shown that dislocation strengthening attributed to extensive CR plays a major role in achieving high strength of this alloy. Besides these macroscopic characteristics, jerky flow caused by the Portevin-Le Chatelier (PLC) instability of plastic deformation was examined. The formation of UFG structure results in a transition from mixed type A+B to pure type B PLC serrations. No such effect on the serrations type was observed after CR.

scholarly journals Особенности упрочнения структурированного интенсивной пластической деформацией сплава Al-Cu-Zr

2021 ◽  
Vol 63 (10) ◽  
pp. 1572
Author(s):  
Т.С. Орлова ◽  
Д.И. Садыков ◽  
М.Ю. Мурашкин ◽  
В.У. Казыханов ◽  
Н.А. Еникеев
Keyword(s):  
High Pressure Torsion ◽  
High Strength ◽  
Coarse Grained ◽  
X Ray Diffraction ◽  
Microstructural Parameters ◽  
Transmission Electron ◽  
Ultrafine Grained ◽  
Preliminary Annealing ◽  
Coarse Grained State ◽  
Additional Hardening

The effect of small additions of copper on the microstructure and physic-mechanical properties of an ultrafine-grained Al-1.47Cu-0.34Zr (wt%) alloy structured by high pressure torsion after preliminary annealing at 375 °C for 140 h has been studied. As a result of processing, high values of strength characteristics (conditional yield strength 430 MPa, ultimate tensile strength 574 MPa) with an acceptable level of electrical conductivity (46.1% IACS) and ductility (elongation to fracture ~ 5%) have been achieved. On the basis of the microstructural parameters determined by X-ray diffraction analysis and transmission electron microscopy, hardening mechanisms responsible for such high strength have been analyzed. It was shown that Cu plays the key role in strengthening. The addition of copper significantly contributes to grain refinement and, consequently, to grain-boundary hardening. Alloying with copper leads to significant additional hardening (~ 130 MPa) in the ultrafine-grained alloy, which is not typical for coarse-grained state. Segregation of Cu at grain boundaries and the formation of Cu nanoclusters are the most probable reasons for this hardening.

Ultrafine Grained High Strength Low Alloy Steel with High Strength and High Ductility

2010 ◽  
Vol 654-656 ◽  
pp. 238-241 ◽  
Author(s):  
Jie Shi ◽  
Wen Quan Cao ◽  
Han Dong
Keyword(s):  
Electron Microscopy ◽  
Alloy Steel ◽  
Volume Fraction ◽  
High Strength ◽  
Uniaxial Tensile ◽  
X Rays ◽  
High Ductility ◽  
Low Alloy Steel ◽  
Uniaxial Tensile Testing ◽  
Ultrafine Grained

In this study a C-Mn High Strength Low Alloy steel (HSLAs) was processed by quenching and austenite reverted transformation during annealing (ART-annealing), which results in an ultrafine grained duplex microstructure characterized by scanning electron microscopy equipped with electron back scattered diffraction, transmission electron microscopy and x-rays diffraction (SEM/EBSD, TEM and XRD). Microstructural observation revealed that the full hard martensitic microstucture gradually transformed into ultrafine grained duplex structure with austenite volume fraction up to 30% at specific annealing conditions. Mechanical properties of this processed steel measured by uniaxial tensile testing demonstrated that an excellent combination of strength (Rm~1GPa) and total elongation (A5~40%) at 30% metastable austenite condition in studied C-Mn-HSLAs. This substantially improved strength and ductility were attributed to the strain induced phase transformation of retained austenite dispersed throughout the ultrafine grained microstructure. At last it is proposed that ART-annealing is a promising way to produce high strength and high ductility steel products.

The Analysis of SPD Paradox by Computer Modeling Technique

2009 ◽  
Vol 633-634 ◽  
pp. 231-248
Author(s):  
Igor V. Alexandrov ◽  
Roza G. Chembarisova
Keyword(s):  
Plastic Deformation ◽  
Thermal Treatment ◽  
Deformation Behavior ◽  
High Strength ◽  
High Ductility ◽  
Angular Pressing ◽  
Deformation Twins ◽  
Ultrafine Grained ◽  
Favorable Conditions ◽  
Dislocation Density Increase

The paper has viewed the manifestation of the paradox of severe plastic deformation (SPD), caused by the occurrence of preexisting deformation twins in ultrafine-grained Cu, which has been obtained by the combination of the SPD method, accomplished by an equal-channel angular pressing with the conventional methods of deformation-thermal treatment. The high strength of the obtained samples has proved to be conditioned by the occurrence of the high density of the coherent twin boundaries, serving as effective obstacles on the way of slipping dislocations. Moreover, the occurrence of the twins creates favorable conditions for the dislocation density increase both in the grains with the twins and in the grains without them. As a result the sample hardens, contributing additionally into its strength. Simultaneously it manifests high ductility. By doing so the deformation behavior of the sample is mainly conditioned by the grain boundaries of grains free from the twins. The results were obtained on the basis of the dislocation-based model which develops models of Y. Estrin and L. Tóth, M. Zehetbauer, and L. Remy.

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